One northern iwi leader has called the replacement foreshore and seabed legislation "evil" but concedes he will have to work with it to negotiate a deal.

Te Runanga o Te Rarawa is one of the few iwi organisations that has started foreshore negotiations, but the status of the law and the Government's review have held up progress.

The coastal iwi's rohe, or region, takes in Ninety Mile Beach. Runanga chairman Haami Piripi said while his iwi was well placed, many whanau and hapu would struggle to apply within the six-year period for customary title, which is a limited form of ownership over the tidal area which can't be sold.

"It's an evil little piece of legislation.

"What it forces iwi to do is to spend thousands of dollars on historical research; that's before you even know if you have a winnable case.

"The fact that there's a six-year time limit just serves to lock out iwi."

Mr Piripi said it was also unfair that port companies would be able to seek fee-simple title for reclamations on foreshore but Maori would be able to apply only for customary title.

In Northland, the Ngati Rehia hapu owns Maori freehold land which abuts Takou Bay and is likely to be a successful contender for customary title because it's likely to pass qualifying tests which say Maori must prove exclusive use and occupation of an area since 1840.

Takou Bay landowners must also show they've held the land in accordance with tikanga.

Shareholder Nora Rameka said Ngati Rehia would decide how to deal with its foreshore after the Waitangi Tribunal finished investigating the hapu's claim that its chiefs did not give up sovereignty on signing the Treaty.