The war memorial's $500m expansion has hit a roadblock after companies withdrew from the project despite being earmarked for potential contracts.
The companies could no longer deliver due to other work priorities, according to the listing.
The project's executive program director Wayne Hitches said since the tender's expiry in March, circumstances had changed for two of the successful companies.
One had received a very large tender outside of the ACT while the other could no longer deliver the services due to organisational changes.
"To ensure the best value-for-money for the taxpayer, the memorial is looking to replace the contractors who have withdrawn," Mr Hitches said.
"Contractors are not secured to the project until a tender is accepted and a contract signed."
Three contractors were originally shortlisted to complete the construction of the new Anzac Hall once approved. Five were on the shortlist for the CEW Bean Building plans while four were eyed for the redevelopment of the southern entrance.
The major works, which have not yet been approved by the National Capital Authority, will overhaul the national institution, expanding the gallery space for more recent conflicts.
The plans include a new southern entrance to the memorial's lower floors, an extension to the Bean building, the refurbishment of the main building and a new Anzac Hall. The facade will remain the same.
Early works were approved this year and began in June with the removal of a number of trees along Treloar Crescent.
Construction workers and heavy machinery soon rolled in early July to undertake the task of pulling down the 20-year-old Anzac Hall.
It's expected the hall's demolition will be completed by mid-September.
A new, larger Anzac Hall will be built in its place once approved and will host a collection of items from more recent engagements in Syria and Afghanistan.
The changes form part of a 10-year plan to expand the Australian War Memorial, which is expected to cost half a billion in total.
Apart from the demolition of Anzac Hall, initial plans also include an extension to the underground car park and excavations to prepare for a new southern entrance.
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