Civil and mining contractors often carry wages, fuel and equipment costs for weeks before a client pays. Add a rejected portal invoice or a retention held for 12 months, and a profitable job can still drain the bank. This guide covers the bookkeeping problems specific to resource and civil supply chains, and how construction finance services keep cash moving.
Published: October 2026
Most small business bookkeeping assumes you send an invoice and the customer pays it. Contractors to miners, councils and head contractors work differently. Invoices go through procurement portals, payment depends on purchase orders and service entry sheets, and contracts often hold back part of each payment as security.
The result is a long gap between doing the work and seeing the cash. Good bookkeeping shortens that gap and makes sure nothing falls through it.
Large mining and infrastructure clients usually require invoices to be lodged in a procurement portal, such as SAP Ariba or Coupa, rather than emailed. The portal checks each invoice against a purchase order, and often against a goods receipt or service entry sheet raised by the client's site team.
An invoice is often rejected or left on hold when:
A rejected invoice does not always send an alert. Weeks later, someone notices it was never paid, and the payment clock starts again from scratch.
The fix is a weekly portal check. Every invoice in Xero is matched to its portal status: submitted, approved, scheduled or rejected. Rejections get corrected the same week. Our guide to effective credit control strategies covers the follow-up process.
Terms vary by client and contract. Many large miners have signed up to the Business Council of Australia's Supplier Payment Code, which commits signatories to paying small business suppliers within 30 days of a correct invoice. Larger suppliers and subcontractors to head contractors often wait much longer.
You can check how fast a large client actually pays. The Payment Times Reporting Scheme requires large businesses to report how they pay small business suppliers, and the results are published on the Payment Times Reports Register.
The cost of slow payment adds up. A hypothetical contractor billing $500,000 a month whose debtors average 60 days instead of 30 has about $493,000 more cash tied up at any time ($6 million a year divided by 365 days, times 30 extra days). Our article on the real cost of 30-day payment terms shows how to price that into your rates.
Many civil contracts hold back a percentage of each progress payment, or require a bank guarantee, until practical completion and the end of the defects period. Retentions are your money, but they are easy to lose track of over 12 to 24 months.
Good practice is to:
Each state has its own security of payment laws, which affect how progress claims and payment schedules work. Our guide to subcontractor vs head contractor accounting explains the basics.
Civil and mining work is priced per job, so profit should be measured per job too. Set up tracking categories in Xero for each contract, and code labour, plant hire, fuel, materials and subcontractors to them.
Without this, a contractor can win more work while losing money on half of it. Our guide to job and project profitability walks through the set-up, and the project profitability calculator for builders gives a quick check.
If you pay contractors for building and construction services, you may need to lodge a TPAR with the ATO each year. Our TPAR guide covers who must lodge and the due date.
Every state and territory runs a portable long service leave scheme for the building and construction industry, funded by employer levies or contributions. Whether civil or mining work is covered depends on each scheme's definitions, so check every state you work in. Our guide to portable long service leave covers how the schemes work.
Off-road use of diesel in heavy plant and equipment can qualify for fuel tax credits, claimed on your BAS. Rates change regularly, and fuel excise was temporarily cut from 1 April to 2 August 2026 (see the ATO fuel response), so check the ATO's fuel tax credit rates for business for the date you bought the fuel before each claim.
Site crews may be covered by different awards depending on the work, and rosters with overtime, allowances and travel make payroll complex. Since 1 July 2026, super must also reach each employee's fund within 7 business days of payday. Our outsourced payroll services handle award interpretation and Payday Super.
Why do mining clients reject invoices?
Usually because the invoice does not match the purchase order, the client has not raised a service entry sheet, or supplier details do not match their records. A weekly portal check catches these early.
How long do mining companies take to pay contractors?
It depends on the client and your size. Many large miners have committed to paying small business suppliers within 30 days of a correct invoice. You can check reported payment times on the Payment Times Reports Register.
How should I record retentions in Xero?
Record them in a separate retentions receivable account on the balance sheet, with a register showing each contract, amount and release date.
Do civil contractors need to lodge a TPAR?
If you pay contractors for building and construction services, you may need to. Check the ATO's rules or our TPAR guide for your situation.
Can contractors claim fuel tax credits?
Often, for fuel used in heavy vehicles and off-road plant in the business. Rates change regularly, so check the ATO's current rates before each claim.
What is a service entry sheet?
It is a record the client creates to confirm a service was delivered. Many portals will not approve an invoice until the matching service entry sheet exists.
What does job costing mean for a contractor?
It means coding every cost and every dollar of revenue to the contract it belongs to, so you can see profit by job rather than only for the whole business.
Book a 30-minute call at calendly.com/scalesuite/30min. We will review your aged receivables and portal status and show you where cash is stuck.
Scale Suite is a Sydney-based provider of outsourced finance teams and fractional CFO services for Australian SMEs. We deliver weekly bookkeeping, payroll, BAS/IAS lodgement, cashflow reporting, management accounts, and strategic fractional CFO oversight, all as a fully embedded team that works inside your business.
CA-qualified, Xero Certified, and registered BAS Agents, we replace fragmented bookkeepers and once-a-year accountants with one responsive finance function at a fraction of the cost of full-time hires. We serve growing businesses across Sydney, Melbourne, Brisbane, Perth, and Adelaide, with packages starting from $1,500 per month and no lock-in contracts.
Visit Scale Suite | View Our Finance Services | View Our HR Services | Get Your Free Proposal
We review and check this guide periodically. At the time of writing (October 2026), all information was current. Scale Suite is a registered BAS Agent, not a licensed tax advisor or financial advisor. This content is general information only and does not constitute professional tax, financial, or legal advice. Some details may change over time.
All figures as at October 2026. Worked examples are hypothetical.
Scale Suite is a Sydney-based provider of outsourced finance and HR services for Australian SMEs. We deliver bookkeeping, financial reporting, payroll processing, fractional CFO support, recruitment, employee onboarding, people and culture support, and fractional HR oversight, all as a fully embedded team that works inside your business.
Employment Hero Gold Partner, CA-qualified, and Xero Certified, we replace fragmented finance and HR processes with one responsive, senior-level function at a fraction of the cost of full-time hires. We serve growing businesses across Sydney, Melbourne, Brisbane, Adelaide, and Perth, with packages starting from $1,500 per month and no lock-in contracts.
30 minutes with our team.
We will review your current finance setup, compare the full cost of an internal hire against our embedded team, and show you exactly what your finance function should cost at your stage of growth.
You will leave with a clear view of what is working, what is missing and where you would save.
No lock-in contracts. 30-day money-back guarantee.
Prefer to book directly? Grab a time here.
