Rep. Stephen Lynch (D-Mass.), himself a former local union president, could be facing a primary challenge from a labor official from the Bay State.

The Boston Globe reported Monday that Mac D'Alessandro, a regional political director for the large service worker's union SEIU, is seriously weighing a run against the sixth term lawmaker, who was the only Massachusetts Democrat to vote against the Democrats' healthcare bill last month.

Here is more from the Globe:

D’Alessandro, who has worked for the Service Employees International Union for nine years, downplayed the role that Lynch’s health care vote played in his decision to jump into the race, saying instead that he wants to bring a different voice to Capitol Hill.

“This is a personal decision for me, as a constituent, as someone who has progressive values,’’ he said. “This isn’t part of me being recruited, no, this is my wanting a stronger voice for the district, for my family and the other families.’’

Asked if he would have voted in favor of Obama’s health care reform bill, he said, “Absolutely.’’

“I’m going to be on the side of consumers and workers, and not on the side of health insurance companies and big banks,’’ he said.

But for now, he said, he is focused on getting on the ballot. “We’ll have more to say once we do that,’’ he said.

State Democratic Party chairman John Walsh welcomed the announcement of a potential new candidate for the state’s Ninth Congressional District, which includes parts of Boston and extends south of the city into Norfolk, Plymouth, and Bristol counties.

“I think it’s a sign of a healthy party that there’s a discussion and a debate,’’ Walsh said.

D'Alessandro has until May 4 to collect the 2,000 signatures necessary to appear on the ballot. Lynch already faces two opponents already, one a Republican and the other an independent.

Some liberal activists have encouraged primary challengers to run against Democrats who voted against the healthcare bill, another sign that the massive $940 billion new law will play a major role in the fall midterm elections.

Walsh told the Globe that the challlenge would be an “uphill fight’’ for D’Alessandro, but said its result is not a foregone conclusion.