A National-led Cabinet would decide which crucial projects to fast-track under its plans to shake up the Resource Management Act (RMA), party environment spokesman Nick Smith says.

National says fixing the act would be one of its priorities if it wins this year's general election. It wants to introduce a two-phase system in which priority consents would have to be processed within nine months.

The proposal, announced by party leader John Key and Smith at the weekend, has generated cautious interest.

However, observers want to ensure community consultation is still an integral part of the process.

Under the act, the environment minister can "call in" a proposal if it is considered of national significance, effectively bypassing local and regional council involvement and referring it directly to a board of inquiry or to the Environment Court.

Only three projects have so far been called in Transpower's North Island grid upgrade, the Te Waka wind farm in Hawkes Bay and Contact Energy's Te Mihi geothermal power station proposal near Taupo.

Meridian Energy's aborted Project Aqua hydro scheme was due to be called in, and recently West Coast councils unsuccessfully asked Environment Minister Trevor Mallard to call in Meridian's planned Mokihinui hydro project north of Westport.

Acting Environment Canterbury chairwoman Jo Kane said she wanted more details.

"We would be concerned as a regional council if anything with this nullified communities' input and the rights of communities to engage," she said.

"There's been a lot of flak about substantial delays in consent hearings and how cumbersome the resource management process was.

"But the timeline in the Environment Court has been reduced and, from a regional council view, commissioners appointed to panels are highly qualified technically and legally. That ensures a very equitable hearing to evaluate complex issues."

She asked who would decide what was of critical importance.

"The biggest to hit us recently is (the) Central Plains (Water irrigation scheme)," she said. "Could that be seen as one of critical importance? What is critical?"

Lincoln University planning and environmental management professor Ali Memon said community consultation needed to be protected, as did transparency and accountability, as big developers could put pressure on the government.

"Changes would need to be carefully handled. It would create a two-tier system a fast track for so-called favoured projects and the normal process for other projects, and it would depend on what criteria they use to define important projects," he said.

"I think a lot of us are waiting to see more details about what they have in mind."

Smith said the full RMA policy had yet to be announced.

"We will include in our RMA reforms this process of priority consenting and we will put in a legislative requirement that such consents will be processed within nine months. It would make a huge difference," he said.

"Who decides what is nationally significant will be up to Cabinet. It's important to emphasise that in the priority consenting process the decision-maker will still need to give legal weight to what is in regional and district plans."

The process would still be transparent and accountable. Involving the Cabinet would mean fast-tracking was less likely to be influenced by big developers than if the decision was left to just one minister, Smith said.

Mallard said: "Everything Nick Smith does will remove the right of people to object and I don't accept the process necessarily takes too long."

Wind Energy Association chief executive Fraser Clark said he wanted to hear more about the planned changes.

"There's an element of risk that if you divorce local authorities from the process too much and we can be talking about 25-year-plus projects if you get off to a bad start, you can have a lot of ill-feeling there for a long time."

The Institution of Professional Engineers New Zealand called for the streamlining of the act in its blueprint for the future launched last night.

The plan said "unnecessary impediments" in the regulatory environment had to be removed.