Passed by the Legislative Assembly on Thursday, the law's wording is not nearly so clear, saying the government can declare a project "related to light rail" if it is infrastructure within, or partly within, one kilometre of existing or proposed track.

Planning Institute of Australia ACT director Hamish Sinclair held "grave and deep concerns" about the integrity of the planning system with the law in place and Institute president Viv Straw had sought an urgent meeting with government before it was passed.

Attempts by the opposition to amend the law were defeated. Liberal planning spokesman Alistair Coe said it was "fundamentally flawed" and Speaker Vicki Dunne accused the government of shutting out the public "in an act of cowardice".

The law does not specify "light rail infrastructure" and, on the face of it, allows any infrastructure within one kilometre of a track - it gives examples of relevant infrastructure, including access roads, footpaths, bike lanes, parking, electricity substations, stops and stations.

Greens minister Shane Rattenbury said the bill facilitated a key part of his agreement with the Labor government. He said the bill came after community members rejected the government's previous attempts to pass fast-track planning laws and called for project-specific legislation.

"This bill does not create an overall precinct and it does not simply override entity advice," Mr Rattenbury said.

Inner South Community Council chairman Gary Kent, who has urged the government to rethink the new laws, said the wording was sloppy and could take in projects like cycle paths or footpaths unrelated to light rail.

He questioned whether it was a drafting error or deliberately left broad, and said the wording should be tightened to get rid of the ambiguity.

Appeals against light rail-related infrastructure are banned and the law allows the government to ignore conservation, heritage and other advice. It also allows the minister to truncate any Assembly inquiries into Territory Plan changes on light rail to three months, and reduce the amount of documentation required.

Planners are also concerned about the amount of land taken in - one kilometre of land each side of the the track would include most of the the central city – and it would be easy for any developer or government to argue any project if that are was "related to light rail".

They are also concerned at the possibility of a broad interpretation of the word "infrastructure", pointing out a ticketing office on top of a multi-storey development could bring the entire development within the definition of infrastructure.

The law covers not only construction but maintenance, relocation and other future work. And it covers any extension of the track to other parts of the city.

Mr Barr insisted the law applied only to light rail infrastructure, "not residential buildings, not commercial developments, just infrastructure associated with light rail - we've been very clear about that".

Asked for clarification, his office said the "wording sufficiently covers the intention of the legislation, in that it will only apply to infrastructure related to the light rail project".

However, the law allows the government to declare that an infrastructure development is "related to light rail", and Planning Minister Mick Gentleman conceded that it would be "the minister and EPD [Environment and Planning directorate] and of course Capital Metro and the government that decide what is light rail".

"It is important to, I think, give the message to people that want to invest in light rail that this is a good project and it is going to be met in a timely manner," he said.

ACT Heritage Council chairman Duncan Marshall said he was disappointed the council hadn't been consulted about the new laws, but he was relatively unconcerned about the changes.

Though heritage issues could arise and advice could be ignored under this legislation - including issues in any extensions of light rail to other parts of the city - he expected the government to consult on heritage early in development.

"So long as heritage expertise is bolted on to the planning process in a very detailed way … early in the process, then I think the system can work OK," he said.