Iwi are calling for the release of confidential documents outlining discussions between the Crown and the Rena's owners over a $10.4million payout to leave the wreck on the reef.

The calls are part of the urgent Waitangi Tribunal hearing in Tauranga today where three iwi groups claim leaving the wreck on the reef is a breach of the Treaty of Waitangi.

Motiti Island hapu spokesman Buddy Mikaere says leaving the wreck is a breach of the Treaty of Waitangi.

The Rena owners Daina Shipping and insurers The Swedish Club have applied for resource consent to the leave the remains of ship on Astrolabe Reef, about 25km off the coast of Tauranga.

Hapu are also calling on the Government to enforce a Maritime New Zealand statutory notice, which says the wreck must be removed.

In October 2012 the Rena owner's agreed to pay the government $27.6million to settle claims of the Crown and public bodies arising from the grounding. A further $10.4million would be paid if they succeeded in obtaining resource consent to leave the wreck in place, as a reflection of further salvage costs.

Lawyer for Ngai Te Hapu, Tom Bennion, saysone big question hinging on the hearing is whether the Crown knew the reef is taonga [sacred], to begin with.

He believes the Crown agreement fails to recognise the reef as a taonga, instead using concerns the wreck is of national importance to overshadow and brush aside Maori interests.

'This question remains significant in negotiations and entering into these deeds back in 2012. The Crown seems to have felt that it didn't need to know if the reef was taonga or not,” says Tom.

'National interest didn't exist until the Crown made into the deed.”

The container ship was travelling from Napier to the Port of Tauranga when it struck the Astrolabe Reef at 17knots early on October 5, 2011. The ship later broke up spilling heavy fuel oil and cargo into the Bay of Plenty. The oil and some of the containers washed up along the beaches.

Motiti Island hapu spokesman Buddy Mikaere says since then government has breached the Treaty of Waitangi by making confidential agreements with the Rena owners and insurers.

Buddy says as 'customary owners” of the reef, Ngai Te Hapu, feel they should have been 'first cab of the rank” in terms of being asked what to do, but instead of the Crown began discussions with owners and insurers.

Last November, Buddy learned of the confidential agreement between the Crown, Rena owners and insurers, but to this day is unable to release the documents to the public.

'The one that is important is the wreck removal deed, which is the one with the $10.4million payment attached to it; that's probably the most important of those,” says Buddy.

'It's the fact that they reached this deal without consulting with anybody. It's not just a Maori issue I think, it's a whole community issue because everybody has various reasons why they want this environmental disaster fixed.”

The tribunal hearing to consider submissions and evidence on the Crown's conduct, taking place at the Trinity Wharf Hotel, is headed by Judge Sarah Reeves, Sir Doug Kidd, Tamati Reedy and Ronald Crosby.

The Crown is expected to respond along with cross-examination of Crown witnesses tomorrow.

A third day is set aside should additional time be required.