The Opposition NDP want Manitoba's conflict of interest commissioner and Elections Manitoba to look into a $500 sponsorship at a fundraising event held by the minister of Crown Services.

The NDP say the third hole at the annual Colleen Mayer Classic golf tournament was sponsored by the Insurance Brokers Association of Manitoba and is a clear violation of the rules governing donations by unions or corporations.

Andrew Swan said at a press conference the NDP have asked Manitoba's conflict of interest commissioner and Elections Manitoba to look into the $500 sponsorship.

Mayer, though a written statement, says the Opposition "have their facts wrong."

The NDP sent media pictures from the Sept. 19 tournament showing the hole sponsor as the IBAM.

"This is troubling for a number of reasons," said Minto MLA Andrew Swan.

"Minister Mayer ought to know, should know, that corporate contributions are not allowed for political parties. Even more troubling, minister Mayer is the minister responsible for Manitoba Public Insurance. The Insurance Brokers of Manitoba is a very strong organization, a good organization, but they are in frequent contact with the premier, with ministers, to deal with issues concerning auto insurance in Manitoba," Swan told reporters Tuesday.

In a statement released to the media, Mayer hit back at the allegations.

"The donation in this case was not a corporate donation. The sponsorship was paid for with a personal credit card, and we have confirmed that IBAM did not reimburse the sponsorship costs," Mayer wrote.

NDP provided media with screen captures from social media accounts including Twitter and its website of IBAM showing their signs at the golf course where Mayer's fundraiser was held.

Mayer wrote that the brokers association made a mistake.

"It is unfortunate that IBAM characterized this is a corporate donation when that certainly is not the case, and we will take any and all necessary steps to prove that these allegations are without merit," Mayer said in the statement.

The MLA for St. Vital also took a shot at Swan.

"It is also unfortunate that Mr. Swan, whose personal history of ethical lapses is well documented, would try and pull others down to his level," Mayer wrote.

CBC News has called the Insurance Brokers Association of Manitoba for comment.