New York mayoral debate turns ugly over Anthony Weiner's 'sexting'

Former US congressman Anthony Weiner fell to fourth among Democratic candidates in New York's latest mayoral race poll, but the scandal over his erotic antics made him the centre of attention in a heated debate.

Weiner used his opening remarks in Tuesday's televised debate, held less than a month before a wide-open primary election, to again apologise for his "sexting", which, when it re-emerged last month, knocked him from his perch atop the Democratic pack.

"I have made mistakes," he said. "They have embarrassed myself and hurt my family."

But Weiner's contrite stance didn't last long, as he traded barbs with his rivals, including the race's new front runner, public advocate Bill de Blasio; the party's 2009 nominee, ex-comptroller Bill Thompson; and City Council speaker Christine Quinn.

The night's most searing exchange came when Weiner criticised Quinn's assistance in overturning the city's term-limits law in 2009 to give independent Mayor Michael Bloomberg another four years in office. "I apologised for my personal behaviour," Weiner said. "The speaker refuses to apologise for overturning the will of the people."

Quinn, who frequently allies herself with Bloomberg, did what she rarely does on the campaign trail and brought up Weiner's admission that he traded illicit online messages with women even after he resigned from Congress in 2011 for similar behaviour.