Auckland's Ngati Whatua tribe is closing Okahu Bay beach tomorrow for a tribal event for what is believed to be the first time since it won co-management of the beach in 1991.

It will hold its annual "mokopuna day" on the beach so that it can include water activities for children.

Spokeswoman Sharon Hawke says the event had been held in previous years on the land reserve behind the beach, but organisers wanted to include water-based activities such as kayaking this year.

A public notice in the East and Bays Courier says the beach will be closed to the public from 6am to 4pm, but Ms Hawke says the tribe will be flexible.