Simmering questions about “pay-to-play” practices in District government boiled into public view Monday on the D.C. Council dais, as a lawmaker sought to derail a contract award that has been challenged by one of his major campaign contributors.

Vincent B. Orange (D-At Large) used an afternoon hearing to assail the city’s decision to award Xerox a $33 million, five-year contract to manage the city’s parking meters. The contract, which transportation officials said will improve the way they manage the city’s parking infrastructure, is set for approval Tuesday.

Ever since the city judged Xerox the superior bidder in June 2012, the other bidder, Rockville-based WorldWide Parking, has challenged the decision.

Six months ago, an administrative law judge denied WorldWide Parking’s contract appeal, but the company has proceeded to lobby council members to bid the contract anew.

The company has also become a donor to the mayoral campaigns of three sitting council members. WorldWide Parking, parent company Meisel Holdings and several executives and other companies listing the same Rockville address donated nearly $50,000 in recent weeks.

Much of the money — $20,000 — went to Orange, who reported raising $80,200 in a campaign finance report filed last week. Muriel Bowser (D-Ward 4) and Jack Evans (D-Ward 2) also reported significant receipts from those donors — $6,000 and $18,000, respectively — but did not attend Monday’s hearing.

Council member Mary M. Cheh (D-Ward 3), chair of the council’s Transportation and Public Works Committee, called the hearing.

“I think we have to be very careful to make sure we don’t allow a company to win through politics when it lost through legitimate channels,” she said.

At several points, under Cheh’s questioning, WorldWide Parking chief executive Marc Meisel conceded that his firm scored well behind Xerox on technical criteria, outweighing its lower price.

But Orange said that WorldWide’s lower price — about $46 million less over five years, in the unlikely scenario that all contract options were exercised — should have weighed more strongly in its favor.

“I’m asking questions to safeguard the assets of the District of Columbia,” he said.“The savings could be used to fund important social programs.”

Other council members challenged that argument by turning the discussion to WorldWide Parking’s campaign contributions — two weeks after the council voted unanimously to place new curbs on political fundraising starting in 2015. Among the changes will be much tighter restrictions on “bundles” of donations given by limited liability companies with related ownership.

Cheh questioned Meisel on the recent donations: “I just wanted to ask you, what was it you looked to gain by giving this fairly large amount of bundled money. . . to council members?” she asked. “What were you thinking?”

“Supporting the council members running for mayor,” Meisel said.

That prompted Orange to ask a few questions of his own — to Pedro Alfonso, a District businessman who is a Xerox subcontractor, seeking to establish that WorldWide Parking is not the only firm involved to have sought favor with lawmakers.

Alfonso is a frequent donor to political candidates, as are Xerox lobbyists Max J. Brown and David S. Julyan. They have not aggregated their political giving as aggressively as WorldWide Parking appears to have done nor have they done so in such close proximity to a crucial council vote.

“You’ve made campaign contributions over the years, and I’m assuming to Bowser and Evans and other persons as well, is that correct?” Orange asked.

“Not in the amount of $20,000, I have not,” Alfonso said.

Orange then asked Alfonso about previous donations. “Yes, but not in the amount of $20,000,” Alfonso said.

“And when you made these contributions did you expect anything from me, making these contributions?” Orange asked.

Said Alfonso: “If I would have made $20,000, yes.”

In the hearing and in an interview, Orange denied that the recent donations had prompted his questions about the parking contract, noting that his inquiries dated back more than a year.

So have WorldWide Parking’s donations: Orange reported an additional $10,000 from entities related to the firm — including from Meisel and companies sharing its Rockville address — in the two weeks leading up to Aug. 8, 2012.

That same day, Orange wrote to transportation director Terry Bellamy about the parking meter procurement, saying “it has come to my attention that the bid may have been improperly solicited.”

Orange proceeded to write two additional letters to Bellamy later that year and issue a news release highlighting his move to disapprove the contract award.

In an interview, Meisel denied that the campaign donations were an attempt to gain political influence in a bid to help secure contracts for his company.

“We’ve been three generations of real estate developers and business owners in the District of Columbia,” he said. “We’ve always supported our government as well as our council.”