UPDATE 2-Most of Broadway darkened by stagehands' strike

(Updates throughout with pickets begin, quotes, affected shows, details)

By Chris Michaud

NEW YORK, Nov 10 (Reuters) Most of Broadway's theaters went dark on Saturday when stagehands went out on strike in a dispute with theater owners and producers, leaving thousands of ticket holders seeking refunds and entertainment alternatives.

The strike, which comes just as the crucial holiday season approaches, could last from days to several weeks, both sides in the dispute said.

Refunds or exchanges would be issued for canceled performances, the League of American Theaters and Producers, which represents producers and theater owners, said in a statement.

Picket lines went up in the morning outside the canceled 11 a.m. EST (1600 GMT) performance of "Dr. Seuss' How the Grinch Stole Christmas," with more expected later at other Saturday matinees.

Some 25 other Broadway shows were also canceled, including cash cows like "Chicago," "The Phantom of the Opera," "Wicked," "Hairspray," "Mamma Mia" and "The Lion King."

The theater league said the strike by the stagehands, who have been working without a contract since July, would cost about $17 million for every day it lasts.

Picketing members of Local One of the International Alliance of Theatrical Stage Employees carried signs reading "On strike" outside the St. James Theater, where disappointed ticket holders voiced frustration.

"This is one experience of New York City that some of these kids will never have again," one parent told local media, adding that "nothing compares" to seeing a Broadway show.

Off-Broadway theaters, nonprofit theaters on Broadway and a handful of major productions including "Mary Poppins" and "Young Frankenstein" were not affected by the strike, the latter two having separate contracts.

'IT'S DEVASTATING'

Other popular shows not affected included "The Ritz," "Xanadu" and "The Putnum County Spelling Bee."

"It's devastating," said James Sanna, a producer of "The Grinch" which had just opened before the strike shuttered it. Seven sold-out shows this weekend alone would not be going on, Sanna noted, and "It really hurts."

The theater league issued a statement deploring the strike as "a sad day for Broadway" and for "the harm is does to the city, the industry, and the theater-going public."

Mayor Michael Bloomberg called on both sides to resolve their differences, saying in a statement, "While this is a private labor matter, the economic impact is very public and will be felt far beyond the theaters closed today."

The walkout follows three months of negotiations. At issue is a set of new work rules for stagehands involving how many of them work on a particular show and for how long, as well as what duties they perform. Producers say they have to pay for long stretches of idle time.

A strike authorization vote was held on Oct. 21 and the parent union authorized the strike on Thursday. Union representatives had earlier declined an offer by Bloomberg to mediate the dispute. The mayor reiterated his offer on Saturday.

The last strike to hit Broadway was in 2003 when musicians walked out for four days. Before that it had been nearly two decades since one of the city's main tourist attractions, which brings in hundreds of millions of revenue annually, was affected by a labor dispute.

(Editing by Vicki Allen)