Sir Peter Jackson has undergone surgery after being admitted to Wellington Hospital with acute stomach pains.

The New Zealand filmmaker went to hospital on Wednesday night and had surgery for a perforated ulcer, The Hobbit publicist Melissa Booth said.

He is currently resting comfortably and his doctors expect him to make a full recovery.

Ms Booth said Sir Peter's surgery is not expected to affect his directing commitment to The Hobbit, though there will be a slight delay to the start of filming.

The Hobbit author JRR Tolkien suffered from a perforated ulcer before dying in 1973.

A perforated ulcer is a when an ulcer in the stomach burns completely through the stomach lining, leaving a hole for stomach acid and foods to enter the abdominal cavity.

In 2005, Sir Peter revealed he had lost over 31kg in 10 months, though other reports put the figure at up to 49kg, which he attributed to intense hard work.

Last week, he was reported to be scouting in Fiordland with the help of five helicopters for locations to the films.

His spokesman, Matt Dravitzki, confirmed the filmmaker was location scouting in the Queenstown area before filming starts next month, and that crews were also looking for sites in the North Island.

Warner Bros last year threatened to take the production to Eastern Europe because the films were the subject of a boycott by several international actors' unions, including New Zealand's Actors' Equity.

The studio agreed to keep the movies in New Zealand after the Government changed employment laws and gave millions in tax breaks.