The territory government wrote to the authority in November asking for a corridor preserved for Monash Drive to be removed from the National Capital Plan.

The corridor was pencilled in during the early 1960s as a bypass for the inner north of Canberra and would connect Antill Street with Fairbairn Avenue by cutting through Canberra Nature Park on the eastern side of Hackett, Ainslie and Campbell.

The four-kilometre trail is currently used for walking, cross-country running, horse-riding and mountain biking.

It is home to 40 threatened species listed under the Environment Protection and Biodiversity Conservation Act, including the little eagle, superb parrot, glossy black cockatoo, hooded robin and painted honeyeater.

Building the road would also require the removal of 30 hectares of endangered Yellow Box and Red Gum Grassy Woodland, and cost $104 million according to the ACT government.

Transport Canberra and City Services director-general Emma Thomas told National Capital Authority chief Sally Barnes last year the benefits of the proposed road no longer outweighed the loss of this habitat and the cost, and the road was rendered unnecessary with the Majura Parkway and light rail.

However, Ms Barnes replied that it would be "premature" to remove the road from the blueprint until it was clear how "a number of current metropolitan planning initiatives that will impact on metropolitan traffic movements are finalised and implemented".

This includes not only both stages of light rail but the ACT government's new transport strategy, which could include tolls or a registration pricing structure that rewards people who drive less, as well as the projected increases in density that will come with Draft Amendment 91, which will increase building heights along the Northbourne corridor.

"Once the impacts of all these matters are fully understood and realised, a revised impact assessment report incorporating long-term policy settings and describing full environmental impacts can be prepared. The authority would be in a better position to consider the proposal at that time," Ms Barnes' letter to the ACT government said.

Leaving the road in the National Capital Plan did not commit the ACT government to build the road, Ms Barnes added.

"The retention of the Monash Drive alignment within the plan does however provide future proofing of the arterial road network if required at a later date," she wrote.

However Roads Minister Chris Steel called on the federal government to "protect the bush capital" and overturn the authority's decision.

"While we are in government we will never build Monash Drive and we want to prevent future territory and federal governments from doing so by removing this fictitious road from the map," Mr Steel said.

"This is an environmentally damaging, unnecessary, and expensive road and it should never be built."

Member for the electorate of Kurrajong, in which the proposed bypass sits, Rachel Stephen-Smith said residents of the inner north wanted certainty that the road would not be built in the nature reserve behind them.

"The residents of Watson, Hackett, Ainslie, Campbell, and Reid have a strong connection to Mount Majura and Mount Ainslie and value the bush right on their doorstep. Those who live near the proposed corridor have also expressed concern about noise and extra traffic causing disruption to many suburbs," she said.