Actress Samantha Morton was selfish and behaved like a disturbed child while filming River Queen, says the film's director of photography, Alun Bollinger.

The movie had its world premiere in Wanganui last month and despite mixed reviews is at the top of the New Zealand box office.

Set in the 1860s, it is the story of Irishwoman Sarah O'Brien (Morton), who has a son to a Maori man and finds herself caught on both sides of the conflict during wars between tribes and the British colonial Army.

It was filmed around Wanganui and production was beset with difficulties, including Morton being in hospital with influenza and director Vincent Ward being fired after tension between him and Morton.

Ward was rehired for post-production but in his absence Bollinger took over as director.

"A lot of people had put their heart and soul into it and you don't want to piss that up against the wall," Bollinger told National Radio yesterday.

The film was a challenge as there was never the budget or resources to fulfil the script as it was written.

But this was compounded by Morton, Bollinger said.

"Basically she's the sort of person who's looking out for number one first, which is kind of crazy because it's a team game, you know. The more you can support each other the more likely you are to get a good finished film."

Everybody had an ego, but they needed to be kept in balance, he said.

"When you get someone like Samantha, who certainly in her work is so self-centred and actually selfish - that's how I would describe it - [it's] to the detriment of the project as a whole.
"People say some actors need to work from a position of anger. Well, perhaps that's what it is with Samantha. Perhaps she's had a difficult upbringing. If it were someone who I wasn't working with, I'd just say she was a disturbed child."

They would "lose her" on occasions.

"She might be on set in the morning but not in the afternoon," Bollinger said.

"I remember 'losing' her one afternoon because somebody had shown her a newspaper article that had upset her and that was it for the day. We didn't get her back."

Conditions were difficult filming on the Whanganui River in winter, and Bollinger believed Morton did not know what she was getting into.

"I don't think any of us quite knew what we were getting into, actually. That was one tough winter."

Bollinger worked with Ward on three previous films and said he, too, could be tricky.

"Vincent's not a natural people person, I suppose."

His dumping came as a shock to the crew. Some people felt the film should be abandoned and others said the wrong person was sacked.

But if Morton had been fired, the film would have folded, said Bollinger.

There was talk that Morton put her hand up to step in as director.

Bollinger said he could not understand how someone like Morton "who makes life so bloody difficult for other people, and essentially to a large degree undermines the project", keeps getting work.