Large trees will be able to be pruned without council permission three weeks from today under a last-minute law change passed by Parliament late last night.

MPs approved under urgency changes to the Resource Management Act - including one making councils that dither over resource consents forfeit some of their processing fee.

The bill included two last-minute changes that have angered green groups and Opposition MPs.

The first scraps a right of councils to require permits for tree trimming from October 1.

The second alters the test for deciding whether the public have a say on new developments.

The Government had planned to give councils two years to make lists of individual trees they wanted to protect before scrapping rules covering felling and trimming.

Last night, that two years was cut to three weeks for trimming.

Councils still have two years to complete their lists of protected trees before rules against felling are scrapped in January 2012.

The Resource Management Act (Simplifying and Streamlining) Bill allows landowners to cut down any tree that is not in a reserve or listed in a district plan.

In Parliament yesterday, National's Auckland Central MP, Nikki Kaye, challenged Environment Minister Nick Smith to assure Aucklanders that valuable trees would be listed before 2012.

Dr Smith said he would write to each council in Greater Auckland and ask for its work programme for listing new trees.

The bill does not define what is trimming and what is felling.

Auckland Labour list MP Phil Twyford said that in theory, a landowner could chop a tree to little more than a stump and call it "trimming".

A spokesman for Dr Smith said councils had definitions of trimming in their plans.

But Auckland City development chief John Duthie said his council would be seeking guidance from the legislation.

If it gave none, the council would develop its own guidelines.

North Shore City environmental policy and planning manager Phill Reid said his council was also waiting to see whether Parliament would clarify what counted as "trimming".

"Trimming" that resulted in the death of the tree should be considered felling, he said.

Mr Twyford said councils had made it clear that if the law changed, they would not list anything like the number of trees that were now protected.

Listing individual trees was "a crazy and bureaucratic solution".

Mr Reid said almost all trees on streets in the Auckland region would be affected, because most were not in reserves and so were not exempt from the law change.

A second late change last night restricts public participation in development decisions to projects that "will have or are likely to have" more than minor effects on the environment.

Under the Resource Management Act, the public can comment on and appeal against council decisions on developments only if the project is publicly notified - as about 5 per cent of developments are.

Originally the bill said developments had to be put out for public comment if they "may" have a more than minor effect.

Green MP Jeanette Fitzsimons said the councils were being asked to decide on the balance of probabilities whether significant effects were likely before hearing any evidence from the community.

Dr Smith told MPs he "made no bones" about the fact that the law change shifted the balance from public participation towards reducing costs for developers.