Sir Peter Jackson is continuing to make progress in Wellington Hospital but there is still no exact date on when he will be released.

The filmmaker, who will direct The Hobbit, was admitted to hospital last Wednesday with acute stomach pains and had surgery that night for a perforated ulcer.

No particular date had been given yet as to when he would be released, but it was expected to be in the next few days, The Hobbit publicist Melissa Booth said.

His doctors expect him to make a full recovery.

Wellington Hospital was not able to comment on his condition.

Filming for The Hobbit was due to start next month.

Sir Peter's surgery would delay the start, but was not expected to affect his commitment to the project, Ms Booth said yesterday.

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

A perforated ulcer occurs 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.

Production of The Hobbit has already undergone several issues with the departure of the original director Guillermo del Toro last year and financial problems.

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 the studio millions of dollars in tax breaks.