The Maori Party has lashed out at "appalling" and "racist" reaction to the closing of Auckland's Okahu Bay last Saturday for a Ngati Whatua family event.

Okahu Bay. Source: 1 NEWS

The iwi advertised that the beach on Auckland's waterfront would be closed from 6am to 4pm as it would be holding its annual Mokopuna Day there for the first time.

A number of comments on social media last week about the decision were too offensive and abusive to publish and some people even threatened in posts to "gatecrash" the event.

"The anger expressed over the closing of Okahu Bay for one day of the year so Ngati Whatua can celebrate its tamariki on its own land is appalling," says Maori Party Co-leader Te Ururoa Flavell.

The Maori Party points out the popular beach is part of a 48 hectare "Whenua Rangatira" block owned by Ngati Whatua which includes the reserve behind the beach where the tribe once lived and Bastion Point (Takaparawha) above the bay.

Since 1991, the area has been managed jointly by the tribe and Auckland Council through the Ngati Whatua Orakei Reserves Board.

"Ngati Whatua has given so much to the city of Auckland, including sharing Okahumatamomoe Bay with all residents every other day of the year," Mr Flavell says.

"To see the backlash from locals who begrudge the tribe having one day a year to celebrate their children at the bay is a sobering reminder of how deep-seated racism is in this country."

Fellow Maori Party co-leader Marama Fox says aside from Ngati Whatua's traditional relationship with Okahu, they also have a legal right under the Reserves Act to request exclusive use of a public area.

"No one bats an eyelid when sporting events and other community groups close off a reserve for a day to use for a private purpose.

"So it's galling that some members of the public apply such a blatant double-standard to iwi," says Mrs Fox.