New York ? If city transit workers strike and shut down bus and subway lines Monday as threatened, just about every aspect of New York’s economy would be affected, from florists to restaurants to major department stores.

The effects could ripple through the national economy, as well, analysts say.

Mayor Michael Bloomberg’s administration has estimated that a transit workers’ walkout would cost the city $100 million to $350 million a day – a figure that includes police overtime, lost productivity, lost retail sales and taxes.

Saturday, negotiators were trying to reach a three-year contract agreement for the 34,000 transit union workers.

If the union decides to strike after the contract expires at 12:01 a.m. Monday, even going out for a meal could be affected.

“Restaurants will move heaven and earth to stay open,” said Chuck Hunt, executive vice president of the State Restaurant Association. “But they can’t run them without sufficient employees.”

Department stores would lose shoppers and crucial holiday sales. Businesses outside the city would suffer, too.

“Because of New York’s pre-eminence in the national and global financial markets and the corporate world, this will be detrimental to businesses throughout the United States,” said Anthony Savino, professor at St. John’s University.

The union would face legal ramifications if it strikes. A judge issued a restraining order Friday that reinforces the state’s Taylor Law, which bars strikes by public employees. The union has appealed.