Actor James Nesbitt has left the set of The Hobbit to return to Northern Ireland, following the death of his mother, May.

The 79-year-old was suffering from Alzheimer's Disease.

In a statement, Nesbitt said: "Mum passed away on Friday night and the whole family is devastated by the news."

Nesbitt has been living in Wellington with his wife Sonia and their two daughters Peggy and Mary while he plays dwarf Bofur in Peter Jackson's Lord Of The Rings prequel.

In a 2010 interview, Nesbitt said he and his family were doing their best to cope with his mother's debilitating condition.

"On my last visit she did not know me but she knew dad. You just have to deal with it and we have responded as a family," he said.

"Dad really rose to the challenge and has dealt with it. He is so thankful that he had 50 years of marriage with mum before this really begun."

- © Fairfax NZ News