Workers picket outside the set of 'The Biggest Loser'

Workers picket outside the set of 'The Biggest Loser' (KTLA-TV / November 15, 2010)

CALABASAS, Calif. ( KTLA) -- Tension is growing outside the Calabasas set of the reality TV show 'The Biggest Loser' as striking workers confront their replacement crew.

Some 50 crew members have been on strike since last Wednesday. They're seeking a union contract with the International Alliance of Theatrical Stage Employees, or IATSE, that would provide pension and health benefits. But, production companies won't sign the deal, saying they already pay above union scale.

Picketers have been confronting fellow workers who cross the lines outside the King Gillette Ranch, located at 26800 West Mulholland Highway.

Striking workers say the NBC series is the last of the big reality shows that is non-union.

Picketers were anxiously awaiting the arrival of the show's host, Alison Sweeney, and two trainers, Bob Harper and Jilian Michaels, to see if they would cross the picket lines.

Sweeney has a no strike clause in her contract. Harper and Michaels are members of AFTRA.

'The Biggest Loser' is produced by Reveille Productions, 25/7 Productions and 3 Ball Productions.

The production companies have threatened to permanently replace the striking workers.