However Mr Quinn, a list MP based in the Hutt South electorate, doesn't see what the fuss is about.
Labour MP Grant Robertson wrote to the commission after receiving a flyer about an event Mr Quinn was organising "in association with" Work and Income in Lower Hutt on November 30. Mr Robertson felt the event breached the public service code of conduct around impartiality and political neutrality.
"The notion of a government agency co-hosting an event with an MP from any particular political party seems to run counter to this principle," he wrote.
Guidelines state agency resources should not be used for party political purposes.
"While it is no doubt desirable for members of the community to know about the programmes that are available, it is not appropriate for Mr Quinn to be hosting an event such as this, particularly in association with Work and Income."
If a politician was to be involved it should be Social Development and Employment Minister Paula Bennett, but even that would be questionable, he wrote.
State Services Commissioner Iain Rennie said the promotional material about the event was "concerning and I can see why you have forwarded it to me".
He asked Social Development Ministry chief executive Peter Hughes to investigate further.
Mr Robertson said in a statement that Mr Quinn seemed to think the public service was an extension of his party's operations.
"The neutrality of the public service is an important and carefully protected balance in our system," he said.
"By his actions Mr Quinn is politicising the public service." Mr Quinn said he would be happy to discuss the matter with Mr Hughes but could not see a problem.
"I've got lots of free advertising for the seminar," he told NZPA.
"I am struggling to see what the complaint is. I am interested in assisting community groups and employees to ensure they are fully informed about opportunities they can provide youth -- that's my focus."
He did not see that the promotion benefited him.
"My office was approached to organise the seminar."
The description of "in association with" was simply factual, he said.
"I am hosting a public seminar at which Work and Income are going to promulgate their programme to employers and community groups about providing opportunities for youth groups," he said.
He said that former Prime Minister Helen Clark had done similar things: "TPK used to organise large hui for Helen Clark to promulgate herself."
