More trouble for New Jersey Governor Chris Christie amid bridge scandal

A rumbling political scandal involving the administration of New Jersey Governor Chris Christie has expanded, ratcheting up the pressure on the eve of his annual address to state legislators.

New documents released by Jersey City officials suggest the Republican Christie administration punished its Democratic mayor last summer by cutting off his access to top state officials when he declined to back the governor's re-election bid.

And in Washington, auditors have begun looking into Christie's use of Hurricane Sandy recovery money to pay for an expensive tourism marketing campaign last year starring him and his family.

It was revealed last week that top aides to the governor deliberately caused major traffic jams in Fort Lee in an apparent plot against its Democratic mayor, Mark Sokolich.

As Christie finalised his state- of-the-state speech, Democratic lawmakers announced the creation of a special investigative committee with subpoena power to further scrutinise the traffic-jam scheme.

The developments compound the political challenge Christie faces in trying to move past the controversy, which began as a local furore over blocked access lanes to the George Washington Bridge before exploding into a national story that threatens his future as a leading Republican presidential candidate.

"This started as an inquiry into the Port Authority and now the trail leads directly into the governor's office," said state assemblyman John Wisniewski, who will head the assembly's investigation of the bridge episode. "The scope of our investigation has gotten considerably larger, and it's clear there was an inappropriate use of power."