An investigation has been launched after a councillor allegedly complained that a voter with learning difficulties "shouldn't be voting".
Officials at Trafford Council in Manchester say they have been made aware of the incident, which allegedly involved an unnamed councillor at a polling station yesterday.
The accusation was made by Kate Green, Labour MP for Stretford and Urmston and shadow spokesman for disabled people. Disabilities charity Mencap said the allegations were concerning.
A council spokesman said: "Trafford Council can confirm it is aware of the situation and that its returning officer, Theresa Grant, was notified last night.
"She immediately launched a full investigation.
"Trafford Council endeavours to make sure all residents who are eligible to vote have the opportunity to do so."
Ciara Lawrence, campaigns assistant at Mencap who also suffers with a learning disability, said: "I have a right to vote and have my voice heard on things that matter to me, just like everyone else does. I went to my local polling station yesterday and cast my vote. That is my right and I won't be denied it.
"People who have ignorant, uninformed views about disabled people should not be in positions of power. Councillors should act as role models for their community, not needlessly insult the people that look up to them.
"Discriminating against disabled people is just as bad as racism and homophobia. There is no difference. Yet some people think it is okay to treat people with a disability as second class citizens."
The allegation is the latest involving councillors making disparaging remarks against disabled people.
Last month Nick Martin, Swindon's Conservative mayor, quit after being ordered to apologise by a standards watchdog.
The 63-year-old was overheard to say at a meeting last year: ''Are we still letting those Mongols have sex with each other?''
And Cornwall councillor Collin Brewer, 68, also resigned - twice - for his ''outrageous and grossly insensitive remarks'' comparing disabled children to deformed lambs.
Brewer first resigned as a councillor for Wadebridge East in February last year when comments he made to a charity worker in 2011 about disabled children costing the authority too much money became public.
But in May he was re-elected to the ward by just four votes and a week later gave an interview to the Disability News Service, which led to his second resignation.
Brewer raised concerns about the ''burden'' of disabled children and compared the costs of looking after them to the maintenance of public toilets.
He compared farmers' treatment of deformed lambs to the way disabled children are dealt with.
''If they have a misshapen lamb, they get rid of it. They get rid of it. Bang,'' Brewer said.
After the comments were published, the council received 180 complaints and a campaign was launched to force him to resign as the independent councillor for Wadebridge East.