PHILADELPHIA (AP) _ A luxury liner with 1,360 people aboard lost power and ran aground Sunday, but instead of triggering panic, it was a chance to ''party hardy a little longer,'' passengers said.

Nobody was in danger, the Coast Guard reported, and passengers on the 642- foot Regent Star said they were enjoying free champagne cocktails supplied by the crew.

Initial attempts to free the ship with tugboats failed and the Coast Guard said another attempt would have to wait until high tide, about 2 p.m. Monday.

The tugs were going to try at high tide after midnight Sunday, but Lt. James Weakley said the Coast Guard felt ''it would be better to try it in daylight'' for safety reasons.

The shipping company, Regency Shipping, must pay for the operation, but the Coast Guard will supervise, he said.

A small electrical fire in a switchboard apparently caused the power failure around 1 a.m. on what was to be the last day of a seven-day trip from Montego Bay, Jamaica, to Philadelphia. The Regent Star drifted into a sandbar 22 miles north of Cape May in the Delaware Bay separating Delaware and New Jersey, according to Petty Officer John Brazell, a Coast Guard spokesman.

''The lights went out in the disco, everybody was singing 'Hot, hot hot,''' Kathleen Hopkins, a reporter at the Elizabeth Daily Journal who was on board, said by phone.

Later, they sang Christmas carols and played an improvised version of ''The Newlywed Game.''

''People started chanting 'Drinks, drinks drinks,''' and free mimosas started flowing, Hopkins said. ''Nobody's really scared, everybody is having a good time.''

''I think it's fun, one big party,'' said Brian Forman, a computer consultant from Philadelphia. ''The party is never going to end.''

''It just gave us a great opportunity to party hardy a little longer,'' Barbara Sowden of Wilmington, Del., said by phone. ''We don't need a band, we make our own music.''

The Coast Guard directed marine traffic away from the area.