Mahesh Chandra, the general practitioner, reportedly refused the man treatment because "he was not British and did not speak English", a GMC committee has been told.
Chandra, who studied medicine in India and has been practicing in Britain since 1971, received a second warning from the medical council last week, following a reprimand last year.
Chandra ran a clinic in Bolton, Lancashire, until his retirement in June 2003. The patient, identified as Mr X, had been staying across the road from the clinic, after arriving in Britain in June 2001 from the Democratic Republic of Congo.
He spoke French, but his 11-year-old daughter was able to speak English, the GMC committee was told.
A witness reported that on that particular day, the asylum seeker was "practically collapsing" at the clinic.
Rebecca Harris, for the GMC, said: "Dr Chandra refused to see him from what he was saying he wouldn't treat someone who'd been dumped on him and wasn't a British citizen. Dr Chandra wasn't prepared to listen and refused his staff permission to call an ambulance.
"Asylum staff had to call for an ambulance, Mr X was taken to hospital and had to be kept in for two days."
Chandra was issued with a warning over the incident earlier this year, which he refused to accept.
Anthony Hopkins, representing Chandra, said: "Dr Chandra does not accept the allegations of Mr X and he does not have any recollection of the incident itself. Dr Chandra is not a doctor who practices by way of prejudice and discrimination."
The GMC hearing issued Chandra a further warning, saying his failings were a "significant departure" from standards.