Anonymous political leaflets posted through letterboxes in Trafford could be in breach of electoral law and have been reported to police.
The handouts are heavily critical of Sir Graham Brady, Altrincham and Sale West's incumbent MP and Conservative parliamentary candidate, and make a series of allegations against him.
The campaign material is unattributable, which isn't allowed under election law, and was posted to homes in Ashton on Mersey around 2.30pm on Monday, November 18.
If a leaflet is pushed through letter boxes during an election it has to contain an ‘imprint’ giving details of who is responsible for it, who paid for it and who promoted it.
Sir Graham said he has reported the leaflets to Greater Manchester Police and met with a Superintendent about the matter.
He said: "I have a record of service to the people of Altrincham & Sale West on which I am proud to stand for re-election.
"It is sad that somebody has stooped to this negative and illegal campaigning. We have referred this to Greater Manchester Police and they are investigating.
"We fully intend to pursue this matter.”
Rob Chilton, Trafford's mayor, confirmed that he has also reported the matter to Trafford Council's chief executive.
It is not clear who is behind the leaflets and other candidates have distanced themselves from the material, condemning it as "below the belt".
Coun Andrew Western, Labour candidate and Trafford Council leader, said: "I condemn this leaflet and distance myself from whoever has produced and is distributing it.
"This sort of politics is not how we work in Altrincham and Sale West and not what we need at a time of such divisive national politics."
Angela Smith, Liberal Democrat candidate, said: "This is deplorable and I want to make it clear it has not been produced or sent by anyone connected to our campaign.
"As a member of More United UK I condemn this sort of thing and believe it should have no place in our politics."
Neil Taylor, Liberal Party candidate, said: "I do indeed [condemn the leaflets], this is underhand and below the belt. The flyers have no imprint so are in breach [of electoral law]."
Geraldine Coggins, Green Party candidate, said: "I was alerted to this leaflet yesterday via Twitter and have no other knowledge of it. At a time when political debate is so divisive and hostile, we need to work in a different way.
"We need to avoid trying to score cheap political points and attacking individuals."