Metrolink in Greater Manchester is being urged to lift its ban on disabled people taking their electric scooters onto its trams.
Four Labour MPs have signed a Commons motion, stating that the decision discriminates against disabled people.
They said it undermined independence and damaged disabled people's quality of life.
They want Metrolink to hold talks with disabled groups on how it "can be made more, not less accessible".
The motion led by Bury South's Ivan Lewis was also signed by fellow Greater Manchester Labour MPs Paul Goggins, Tony Lloyd and Jim Dobbin.
Disability scooter users said they had been able to board trams up until the recent introduction of 40 new yellow trams.
But a Metrolink spokeswoman said that the by-law banning scooters has been in existence since the network was launched in 1992 and that it was now being enforced following an accident.
Metrolink Director, Philip Purdy said: "We recently had an incident at the Besses o'th' Barn Metrolink stop where a man manoeuvring a mobility scooter drove off the platform and fell over 1m on to the tracks.
"Thankfully he was not badly hurt, but we cannot allow this to happen again.
"As a result, we need to ensure the existing by-law is enforced thoroughly but we also accept that, in doing so, we need to remind passengers of the rules.
"We are keen to engage widely to ensure that passengers are aware of the rules.
"We have already formally written to Mr Lewis to explain the situation, but would be happy to meet with him to explain it in person."