The ACT government was advised not to install point-to-point speed cameras on Athllon Drive according to documents published under freedom of information laws.
Government planners told Sustainable Development Minister Simon Corbell the cameras should be relocated because they would conflict with a proposal for a park-and-ride facility on the same stretch of road.
Consultants recommended the government instead install the territory's second point-to-point speed cameras on either Parkes Way or Tuggeranong Parkway, the documents show.
The ACT opposition has accused Mr Corbell of misleading a Legislative Assembly committee, which was told by Mr Corbell in June that the government had never considered locating the cameras elsewhere.
Opposition planning spokesman Alistair Coe said on Tuesday that Mr Corbell had ''stubbornly gone ahead with what is perhaps another very expensive white elephant''.
But Mr Corbell said on Tuesday his responses to the Assembly's estimates committee were accurate and he had told his directorate to instead find a way to accommodate both point-to-point cameras and a potential park-and-ride on Athllon Drive.
The government spent more than $745,000 on installing the set of cameras that covers a 3.8-kilometre stretch of Athllon Drive, between Drakeford Drive and Beasley Street in Canberra's south.
Critics have attacked the decision to monitor average speeds along a stretch of road that requires motorists to slow down for two roundabouts, one of which is a busy intersection with Sulwood Drive.
In five days of testing before the launch of the new cameras, just seven drivers were caught speeding. Now a briefing document shows Mr Corbell was warned in September last year that part of that corridor was considered the best site for a Wanniassa park-and-ride, which would make the area less suitable for point-to-point cameras.
Government planners said a park-and-ride would require the lowering of the speed limit and installation of a pedestrian crossing with lights, which would mean the corridor ''would no longer be compliant with the criteria used to select and rank point-to-point sites''. Four options were given for resolving the problem, including finding a new location for the park-and-ride.
But planners recommended relocating the point-to-point cameras to either Parkes Way or Tuggeranong Parkway even though it could result in up to $150,000 ''worth of capital works already undertaken for point-to-point cameras at Athllon Drive being unable to be utilised''.
Mr Coe called on Mr Corbell to ''explain why he has misled an Assembly committee about his consideration to remove or relocate the point-to-point cameras.'' The deputy opposition leader said ''the revelation that the government was told there would be problems with the Athllon Drive point-to-point camera is another example of the government mismanaging ACT roads''.
Mr Corbell said the government never considered the recommendation to relocate the cameras because it had already funded the point-to-point for Athllon Drive, while the proposed park-and-ride was only at a feasibility study stage.
''The government had funded the point-to-point on advice previously given,'' Mr Corbell said.
''The point-to-point was going to proceed based on advice it was the third highest ranked site for point-to-point in the city.''