All of those groups could have an interest in issues overseen by the House transportation committee, where LoBiondo, a 10-term incumbent, is a longtime member and chairs the aviation subcommittee.
When the Transportation Trades Department celebrated its 20th anniversary in 2010, LoBiondo praised the group in a speech on the House floor, saying he was "proud to work closely" with it.
Hughes questioned the propriety of LoBiondo's overseeing transportation issues while he receives campaign help from a union lobbyist who seeks to influence transportation policy and helps the congressman win political support.
"This is dirty," Hughes said.
Ingrao does not lobby LoBiondo's congressional office, nor does he work for it, said LoBiondo spokesman Jason Galanes.
"It's all perfectly legal. It is reported in the [federal] filings and has always been," he said. "The congressman has no concerns about Mr. Ingrao's dealings outside of working for LoBiondo for Congress."
Ingrao consults on labor relations for LoBiondo's campaigns, Galanes said. He does similar work for several other members of Congress.
LoBiondo's campaign has paid Ingrao $90,232 in 2013 and 2014 - including a monthly retainer of $5,500 and travel expenses - according to the congressman's most recent campaign filings.
LoBiondo paid Ingrao more than $110,000 in his previous two elections, according to the Center for Responsive Politics, making the consultant one of the campaign's top vendors.
Ingrao spent 17 years in the political department of the AFL-CIO. The union endorsed LoBiondo this year. So did powerful police and teachers unions, giving the Republican, whose family once operated a trucking firm, an unusual seal of approval from unions that typically lean Democratic.
When Ingrao returned an Inquirer reporter's phone call Wednesday, he said he had dialed the wrong number and hung up.
Hughes had seemed to win his own labor backing last week when he announced an endorsement from the AFL-CIO-affiliated UAW, quoting the union's South Jersey officials.
But on Wednesday the UAW's regional office retracted the endorsement, saying that some New Jersey members were not present when Hughes met with the union's South Jersey officials. Another endorsement meeting will be held this summer, the news release said.
The dispute appears to be between local groups - Hughes said he met with four UAW locals - and the regional organization.
"It is clear the wishes of the local union leaders - those who have to live with Congressman LoBiondo's ineffectiveness - have been overruled," Hughes said in a news release.
Hughes is the son of William Hughes, who represented the Second District for 20 years before retiring and being replaced by LoBiondo in 1995. The district includes parts of eight South Jersey counties, including Burlington, Camden, Gloucester, and Atlantic.