A group of employees who say they worked in cramped conditions in a Queens basement to build pinatas for a chain of party stores have filed suit, claiming they were underpaid and their working conditions violated labor laws.

The employees say they routinely worked 11-hour days, six or seven days a week, in the basement of a party supply store in Woodside, Queens, where they assembled pinatas.

For their labors, the workers were paid only about $3 an hour and were not paid overtime, in violation of federal and New York state labor laws, the suit says.

The workers were paid in cash “off the books” and worked in the windowless basement without masks and gloves to protect them against the “chemicals and fumes” they were exposed to while constructing the paper pinatas, the suit claims.

The suit – filed last week in Brooklyn federal court – names as defendants the firms Let’s Have A Party II Inc., Balloons Party, Inc., Balloons Pary, Inc., Party Surprise, Inc., and Happy Fiesta Corp.

The workers manufactured around 300 pinatas a week in the basement work room, the suit says.’

The workers, who claim they also were dissuaded from leaving the basement to go upstairs and use the restroom in the party store on the ground floor, are also charging the owners with false imprisonment, the suit says.

mmaddux@nypost.com