Mayor Gavin Newsom remains out of The City — presumably still at a resort in Hawaii — while a labor dispute grows.

Hotel workers at the Grand Hyatt Union Square went on strike Thursday morning.

Nathan Ballard, the mayor’s spokesman, said he has been in contact with Newsom about the hotel strike.

It has been six days since the mayor has appeared publicly following his withdrawal from the 2010 governor’s race. The mayor abruptly left The City on Tuesday morning to join his family on a Big Island resort.

The departure also left questions about whether the mayor followed proper protocol in designating Supervisor Carmen Chu as acting mayor.

Newsom is expected to return Sunday, Ballard said.