Cameras began rolling this week on the latest Terminator movie -- estimated to cost about $150 million -- for what many Hollywood watchers say is a late start given concerns that labour tensions could lead to an actors strike by July.

Terminator Salvation: The Future Begins, began shooting on Monday in New Mexico, bucking a trend in which studios have mostly avoided launching new productions they cannot be sure of completing before the Screen Actors Guild contract expires on June 30, a date being treated as a facto strike deadline.

SAG and Hollywood's major studios hit a stalemate on Tuesday after three weeks of talks, stoking fears of renewed Hollywood labour unrest after a 100-day screenwriters strike that ended in February.

Union leaders say they still hope to reach a deal without resorting to a walkout, and SAG has yet to even seek authorization from its 120,000 members to call a strike.

But with tens of millions of dollars at stake in making a movie, few studios and filmmakers are taking any chances. One exception is the team behind "Terminator ."

Warner Bros, a unit of Time Warner Inc, is the U.S. distributor for the fourth "Terminator " starring Christian Bale and set to reach theaters in May 2009. Sony Corp's Sony Pictures is handling international distribution.

The two studios had a similar deal for 2003's Terminator 3: Rise of the Machines, which grossed $433 million worldwide and was the last film in the franchise to star Arnold Schwarzenegger as the unstoppable cyborg from the future who made the line, "I'll be back," a worldwide catchphrase.

RISKY BUSINESS

A source familiar with the latest sequel said filmmakers have no intention of wrapping production by June 30 and have taken legal precautions in case of a work stoppage. A second person close to the film's production will go on hiatus if there is a strike, but others said that is a risky endeavor.

"I think many productions are planning on wrapping up by the strike deadline. It is often very difficult to stop production midway. Putting a production on hold is a pretty gigantic responsibility," said one executive from a talent agency who spoke on condition of anonymity.

Due to its late production start, Terminator 4 was ineligible for special "strike expense" insurance coverage recently offered by Fireman's Fund Insurance Co.

Wendy Diaz, underwriting director at Fireman's, said many studios rushed ahead with production to get the coverage, which was contingent on shooting being scheduled to end by June 15. The policies reimburse producers for strike losses if filming is delayed past June 30 by unforseen circumstance, such as an actor's illness or equipment damage.

Few, if any, studio movies were put into production after late March or early April, because a typical 60-day movie shooting cycle would cut it too close to the presumed strike deadline.

Steven Spielberg called off an April start to a film about the trial of the 1968 anti-war activists, and Michael Bay is keeping his fingers crossed for an early June start for a sequel to his Transformers.