About 300 people joined hands in Mangere today in a bid to stop a housing project on what an archaeologist calls "the paddock next to Stonehenge".

Fletcher Building has gained Special Housing Area status for a planned 480 homes on the 32ha site next to the Otuataua Stonefields Reserve near Auckland Airport.

Former Conservation Department regional heritage manager Dave Veart told protesters the land is of international significance.

Mr Veart said about 100,000 years ago our distant ancestors set off from Africa to colonise the world, and the last place on the planet they reached was Aotearoa, and one of the first places they reached was Otuataua.

The foundations of houses and gardens date back 700 years to the earliest stage of Maori settlement.

The development block contains at least two lava caves Maori used as burial sites, and Fletchers has agreed to add that part of the site to the reserve.

But Mr Veart said there were almost certainly items of archaeological significance on the rest of the site where housing is planned.