Congressman Patrick Kennedy of Rhode Island has called new US senator Scott Brown "a joke," after he moved up his swearing in to vote against a supporter of labor unions.

“Brown’s whole candidacy was shown to be a joke today when he was sworn in early to cast his first vote as an objection to Obama’s appointment to the National Labor Relations Board,’’ Kennedy told a reporter for the congressional newspaper, The Hill, on Thursday.

“Seven out of 10 of Brown’s voters were labor households and he stressed that he was independent and while he was originally scheduled to be sworn in next week, they moved it up to today so he could cast his first vote, the most anti-labor, the most anti-what his constituents thought they were voting for when they voted for him,’’ Kennedy said.

Reaction was quick for Republicans who believe they have a shot at Kennedy's Rhode Island seat. “Patrick Kennedy’s desperate remarks are an insult to the same voters who revered his uncle and the sure sign of a flailing candidate with abysmal poll numbers,’’ said Jennifer Nassour, the chairman of the Massachusetts Republican Party.

But Rhode Island State Representative John J. Loughlin II, who is running against Kennedy, said the comments were not surprising.

“I’ve seen Congressman Kennedy make some pretty outrageous statements before he ever even knew who I was,’’ Loughlin said in an interview with The Boston Globe. “

A poll on Friday showed Kennedy with only 35 percent support in his district and a 56 percent disapproval rating.