The ACT opposition has accused the government of breaching national disability accessibility standards set a decade ago.
The national disability standards for accessible public transport were implemented in 2002.
Under the standards, the old orange Action buses were supposed to be retired by the end of 20-22.
However, the ACT government claims supply chain issues have delayed the remaining 33 diesel buses to be retired.
Opposition transport spokesman Mark Parton says the government should have been transparent about the continued use of the orange buses – and the delay has impacted people with disabilities.