The Conservation Department has urgently warned ministers that it cannot afford to lose unprecedented quantities of valuable public land being handed back to Maori.

The public will no longer have access to some of the land blocks that are being vested to iwi, including Far North land around Mangonui and Mangatete, and reserves in the Manawatu, Nelson and the Marlborough Sounds.

Negotiators are also discussing the future of more conservation land, including most of Tongariro National Park and some of Te Urewera National Park, as they rush to meet the settlements deadline.

Conservation land is intended to be held in trust for future generations, and previous Governments had promised it would be used for Treaty of Waitangi settlements only in the most unusual cases, where there was no other option.

But documents released to the Herald on Sunday under the Official Information Act show that 163,000 hectares of conservation land has been used in Treaty settlements - three-quarters of that land in the past 12 months.

Most of that is being retained in public ownership, or with public access guaranteed, with the iwi playing a role in managing or naming it.

However, at least 700ha - perhaps as many as 2000ha - have been vested back to iwi ownership with no provision for public access, a DoC spreadsheet shows.

In the Far North, councillor Colin Kitchen said he would be concerned if any Treaty settlements restricted access to beach areas.

"Maori and Pakeha, we've all grown up together, gone to school together," he said. "As far as I am concerned we're all one people."

One Mangonui resident said the vesting back of parts of the local recreation reserves would "cause some grievance" among locals.

"It would certainly cause a bit of ill feeling if we were put off from using it," he said.

Parts of the Mangonui Domain recreation reserve and conservation area, and the Mangatete conservation area, will also be off-limits so the iwi can protect areas of cultural and historical significance like pa sites, or wahi tapu where there is particular spiritual and cultural importance.

The draft settlement, due to be finally signed off this year, will also return several hectares of the Maitai Bay recreation reserve to Ngati Kahu. The iwi's chairwoman, Professor Margaret Mutu, was overseas and unavailable for comment.

Minister for Treaty of Waitangi Negotiations Chris Finlayson, said more than 95 per cent of Conservation land transferred in Treaty settlements had public access protected.

"Restrictions on public access have been made in a few minor and exceptional cases."

The ailing Conservation Department warned ministers last year - as a matter of "high" priority - of long-term financial risks stemming from the loss of revenue-generating conservation land to Treaty settlements.

The financial concerns were coupled with projections of an $8m budget blowout and 60 job losses over the subsequent two years, partly because of work required in dealing with Treaty settlements.

Department officials told Tim Groser, the new Conservation Minister, that Treaty settlements were being sped up at the expense of conservation management.

Despite a Cabinet policy that conservation land was "not readily available for use in Treaty settlements", previous ministers had "frequently" made exceptions in the interests of settling claims, the officials said.

This week, Conservation Department Director-General Al Morrison said the threat of the $8m budget blow-out had prompted the department to rejig its budgets to deal with the increased weight of Treaty settlements. "We've got to sit down and work out what Treaty settlements cost us and we've got to get a lot better at that so we've got a clear business case," Morrison said.

"My concern was, we don't want to take it [funds] out of possum control or building huts."