An auditor-general's report into the Canberra-based institution found conflicts of interest were not adequately documented or declared and that contracts had been split so they would not need ministerial approval.

It also revealed then-prime minister Scott Morrison - who makes a final bow from politics on Saturday when voters choose a new member for his seat - had approved the project before its business case was finalised.

There was "no evidence" it had been considered by government before the controversial upgrade was announced in 2018, the report said.

On Wednesday, a spokesperson for Veterans' Affairs Minister Matt Keogh said he was concerned by the revelations.

"The minister has requested an urgent briefing by the ANAO (Australian National Audit Office) on its findings and recommendations, and will discuss these with the Australian War Memorial's management as a priority," they said.

Opposition veterans' affairs spokesman Barnaby Joyce, however, seemed less concerned by the report's findings.

"We say 'Lest we Forget', we have never said 'Lest we Forget, dependent on a business case'," he said in a statement to AAP.

"While the auditor has identified important improvements for better processes and ministerial oversight, I am supremely relaxed that our government made the decision to announce the project before a business case had been completed."

He maintained Australian veterans should be honoured regardless of the findings in a business case and said the upgrade would create a memorial the nation would be proud of.

"I am uncomfortable when the words 'business case' and 'remembering them' are used in the same sentence - very uncomfortable," Mr Joyce said.

"We didn't send our fine men and women to war based on a business case, they didn't die and get shot-up based on a business case, and we shouldn't decide whether we remember them or not, based on a business case."

The Australian War Memorial's multimillion dollar upgrade, which is slated for completion in 2028, has been mired in controversy from the outset.

Though it is expected to increase visitor space by 83 per cent, the iconic Anzac Hall will be knocked down and rebuilt despite having only been opened in 2001 at a cost of $17 million.

The auditor-general's report, released on Thursday, has added fuel to the fire, revealing one contract with Xact Project Consultants had been varied to $999,999 - one dollar below the threshold required for ministerial approval.

Another contract with Imagination (Australia) Pty Ltd worth $1.05 million was split into two, one worth $841,875.43 and the other $207,659.10.

Both were signed the same day.

The auditor-general made five recommendations including that the memorial improve its records management policies and strengthen the ethical conduct of procurement - all of which have been agreed or agreed in principle.

Australian Associated Press