Sports minister Nigel Adams described the abuse as "disgusting", while new Lib Dem MP Luciana Berger - who quit Labour in protest at the handling of anti-Semitism allegations - called on Uefa to take "tough action".
It came after an England fan died in the build-up to Monday night's match.
England were barely troubled during the routine 6-0 victory over their hosts, but the game was overshadowed by racist behaviour in the stands, forcing the match to be halted twice in the first half and fans were warned about their conduct.
Ms Berger added: "In the face of disgusting racism and such ugly scenes, @England won. But they shouldn't have been subjected to it. @UEFA have to stop this from happening at all. Now."
Labour MP Rosena Allin-Khan offered "absolute solidarity" with England's players, and said she had spoken to the FA after the match.
She said: "There can be no place for racism in football - you have a country behind you tonight. We need fans, clubs, press and politicians to join in solidarity!
"Tonight, I've had a conversation with the FA Chief Exec and made clear that the England team has my full support. UEFA must come down hard on racism - a generation of players and fans are watching. Time to set an example."
Earlier, Bulgarian authorities confirmed the death of a British national.
The unnamed 32-year-old was said to have been acting "aggressively, raging and threatening" when he was discovered at around 10am on Monday ahead of the crunch match in the city.
A spokeswoman for the Ministry of Interior said no cause of death has been identified.
She told the PA news agency: "A 32-year-old man has sadly died.
"At 10am today, the police received a signal to attend a man in a helpless condition, in the city centre.
"He was a foreign national, from Britain, and he was taken to hospital but he sadly died.
"Police are working to clarify all the circumstances in the incident. There is no further detail on any injuries.
"There will be a forensic examination to find out what the cause of death was."
A statement on the authority's website added that in hospital, the victim "suddenly began to act aggressively, raging and threatening".
A Foreign Office statement added: "We are supporting the family of a British man who died following an incident in Sofia, and our staff are in contact with the UK and Bulgarian authorities."