Iwi leaders are fighting to retain ownership of the foreshore and seabed in talks to develop new legislation.

About 100 iwi and hapu representatives met yesterday for a hui amid fears the Cabinet may discuss a replacement for the contentious Foreshore and Seabed Act on Tuesday.

Attorney-General Christopher Finlayson sent a letter to Iwi Leaders Group chairman Mark Solomon on Thursday which outlined the Government's desire to push ahead with its "preferred" option for repeal.

That hinges on no single group owning the area, which would become public domain, instead of the current situation where the Crown owns it.

Ngapuhi leader Sonny Tau said that while leaders wanted a repeal and Crown ownership deleted, the Government-proposed form of ownership was still contentious.

During meetings the group had put it to the Government that ownership should be jointly vested in the Crown and iwi - but that was rejected "outright", he said.

Leaders were also unhappy with the idea that if the proposal became law, the vast majority of foreshore and seabed would become public domain, but 12,500 parcels of land now in private ownership would not be affected.

When the law prevented Maori from going to court and proving ownership, the 12,500 parcels remaining unchanged did not sit well with Maori.

"We said, 'Put those titles in public domain and we'll agree to it' [the Government's plan]."

Mr Tau said the group thought it had reached a position with Mr Finlayson and Prime Minister John Key that after a repeal the onus would not be on Maori to prove foreshore and seabed rights had not been extinguished.

Instead the Crown would have to prove that Maori ownership from 1840 was legally extinguished.

"We felt we had an agreement on that, but it hasn't appeared in the letter," Mr Tau said.

Ngati Kahu leader Professor Margaret Mutu said those gathered wanted the group to push harder.

A spokesman for Mr Finlayson would not confirm whether the issue was on the Cabinet agenda.