"The five other similar sculptures all sit in museums" - Razia Iqbal reports

Carved by the Ngati Kahungunu tribe, the 4ft (1.2m) sculpture used to form the base for a pole that helped support the roof of a tribal meeting house, said Sotheby's African and Oceanic Art Department Director Jean Fritts.

The piece - described by Sotheby's as "a masterpiece of Pacific sculpture ... the most important work of Maori art to be offered at auction" - was probably carved in the 1830s or 1840s. The male ancestor it depicts lived far earlier, and was possibly a tribal chief, Ms Fritts said.

The tribe that carved the piece would like to see it return home

"People would greet the ancestor and touch the figure whenever they came into the meeting house," she said.

"It was a way of reconnecting with the past ... and exactly who you came from."

The identity of the anonymous telephone bidder has not been revealed. It is also unclear whether the statue will be returned to New Zealand, as the Ngati Kahungunu tribe had hoped.

When Sotheby's representatives met the tribe, they expressed interest in the sculpture, but had no plans to bid on it. A tribe spokesman said he hoped New Zealand's national museum would try to buy it.

Many Maori - New Zealand's Polynesian indigenous people - have worked hard to return their cultural treasures to their island nation.

The statute was originally brought to Great Britain by a grandson of William Williams - an English bishop working as a missionary in New Zealand. He helped establish schools for the Maori and translated the New Testament into their language. He was given the piece in the 1870s by Maori from the Hawkes Bay area.

The last owner was a Swiss collector, Philippe Woog, of Geneva, who bought it 20 years ago.