Actresses and unionists have received threats, including some against their lives, during the heated row over The Hobbit movie.

Police have been called and private security arranged for some of those targeted.

The worst threats appear to have been aimed at Australian union boss Simon Whipp and Actors' Equity organiser Frances Walsh, although actresses Jennifer Ward-Lealand and Robyn Malcolm have also been abused.

The threats have become so bad the union has hired a guard for its Auckland office.

Malcolm is selling her home and has pulled back from some high-profile marketing. She was reluctant to comment this week on any abuse.

Mr Whipp, the Australian-based director of the Media, Entertainment & Artists' Alliance who has been in New Zealand during the row, said he and Ms Walsh had both received death threats.

"I don't know that Jennifer has, but she has received some terrible things in the mail."

Verbal death threats were also left as voice mail messages at the Alliance's Auckland office, where Actors' Equity NZ is also based.

Mr Whipp's other threats include abusive emails, Facebook messages and posts which include swearing and threats.

His personal details have also been posted online without his permission.

He has laid a complaint with police in Australia.

A spokesman at Redfern police station in Sydney said staff would take about a week to find out where the threats had originated. If they were traced back to New Zealand, the file would be sent here for further investigation.

Mr Whipp said he was "very surprised" by the intensity of the reaction in the past few weeks.

"I have never seen that before in all my years. Myself and staff have received threats and we have hired a security guard at our office. I have no idea if they [are from] people in the industry."

Mr Whipp said Ward-Lealand - president of Actors' Equity NZ - and Malcolm, the union's public face during Hobbit-related industrial action, had received threats over the past week and verbal attacks in the street.

Yesterday, the Government began pushing labour law amendments through Parliament under urgency as part of a deal with Warner Bros to ensure that the two Hobbit movies are filmed in New Zealand.

Film-makers Sir Peter Jackson and his wife, Fran Walsh, said they were grateful for the legislation, "which shall give everyone in the film industry certainty as to their employment status".

The pair, who were largely instrumental in bringing The Lord of the Rings trilogy to the screen, said the clarification would provide stability and reassurance for film workers as well as investors.

And Sir Peter said he felt enormous gratitude to the film technicians, actors and fans who came out in support of making the films in New Zealand.

"To the thousands of people who took the time to write and let us know they were with us - thank you. It made all the difference."

The legislation marks the end of a bitter row. Last Wednesday, an angry group of Wellington film workers confronted Mr Whipp, Frances Walsh and Malcolm when they emerged from a restaurant around midnight.

Earlier, up to 1500 film workers had marched through Wellington with Weta Workshop chief Sir Richard Taylor venting their frustration at the prospect of losing the $670 million project overseas.

And John Barnett, chief executive of South Pacific Pictures, which produces Outrageous Fortune and Shortland Street, warned that the fallout from the wrangle has made Malcolm and Ward-Lealand "damaged goods" who could struggle to find acting work.

He blamed the unions for not keeping the two actors away from the outcry that erupted over the possibility of losing the two movies.

"The feedback has been quite vocal and critical of them," he said this week. "They've been pushed into the front row and are now earning the opprobrium of the public."