Children's advocate Lesley Max and other prominent Aucklanders are taking legal action to stop the Auckland City Council removing the 20 condemned trees in Queen St.

Lesley Max said the council did not seek or heed the views of Aucklanders when it sought resource consent to remove the exotic trees and replace them with natives as part of the $30 million Queen St upgrade.

The so-called "Queen St massacre" is set for January 13 and 14, although Mayor Dick Hubbard has said he will consider options to keep 20 of the 36 trees tagged for removal between Mayoral Drive and Wellesley St.

"It should not be necessary for citizens to contemplate legal action against the city council that they elected," Lesley Max said.

Resource consent was granted just before Christmas. CBD project leader Jo Wiggins said the application was not publicly notified because the council had already gone through public consultation on the Queen St upgrade and the trees were not scheduled.

Lesley Max has banded with veteran newspaper campaigner Pat Booth, NewstalkZB host Leighton Smith, former Hobson Bay Community Board members Stephen Goodman and Aaron Bhatnagar and several others to take the legal action.

Their lawyer, Matt Casey, yesterday said the group was challenging the resource consent on the grounds the council did not consider the views and preferences of people and should have publicly notified the application because of strong tree protection provisions in the district plan.

"While the council did put out a consultation version of the proposal, it didn't have one that included the destruction of these trees," Mr Casey said.

The group was seeking an interim injunction to stop the council removing the trees while a judicial review takes place. The injunction is due to be heard on Wednesday in the High Court at Auckland.

Acting council chief executive John Duthie said the council's lawyers were looking at the case.

The bill to ratepayers is unknown but will start at thousands of dollars and climb if the case drags on.

Mr Duthie said the group had the right to take legal action but the council believed it had done everything correctly.

He was unsure what effect the legal action would have on the upgrade but said it would not stop the project starting on Wednesday. The first work involved some kerb relocations.

Mr Hubbard told the Herald on Friday that saving the trees would incur a "multimillion-dollar mess" for ratepayers because the council had let the contract on the $30 million project.

Last night, the mayor, who is holidaying in Queenstown, would not comment on the legal action until he was briefed.