Sheffield MP Louise Haigh says she has faced "very explicit" death threats after proposing a debate to decide whether Britain First should be outlawed.
The Labour politician added one individual went through all her videos on YouTube and claimed "he would not rest until I was murdered".
The MP for Sheffield Heeley also told the Commons she has been labelled a "traitor" and a "Muslim lover".
Ms Haigh suggested the threats and abuse were evidence that Britain First should be listed as a "terrorist organisation".
In November, Ms Haigh asked for a debate about whether Britain First should be proscribed as a terrorist organisation and banned from standing in democratic elections.
Speaking as MPs debated a motion to ban the neo-Nazi movement National Action, Ms Haigh said: "I'd also take this opportunity to call on the Government to give time to debate the proscription of Britain First.
"Last month I called for this debate. I didn't call for Britain First to be proscribed, I just called for this House to be given evidence and to look at the details of their paramilitary activity and their anti-democratic behaviour.
"As a result of that and the way that the media covered my call, I have received very explicit death threats.
"I have been called a traitor, I have been called a Muslim lover and on Friday an individual went through every single one of my videos on YouTube and said that he would not rest until I was murdered.
"Now, if that isn't evidence that Britain First should be proscribed as a terrorist organisation then I'm not sure what is - and I hope that the minister will give clear consideration to time in this House to debate just that."
Democratic Unionist MP Jim Shannon (Strangford) followed Ms Haigh's speech, telling her: "Everyone in this House stands with you."
He added: "It's very important you know that we're very much shoulder to shoulder with you and what you do."
Far-right group Britain First has previously organised demonstrations and mosque "invasions" around the country.
It also has a sizeable presence on social media, with more than 1.5 million likes on Facebook.
On National Action, MPs agreed to add it to the list of proscribed organisations - with the order coming into force once it has also been approved by the House of Lords.
It will be the first time a group engaged in extreme right-wing activities will be banned under the Terrorism Act 2000, with the order expected to come into force on Friday.
The move, which means being a member of the organisation becomes a criminal offence, was initially announced ahead of the debate by Home Secretary Amber Rudd.
Speaking in the Commons, Ms Haigh said of National Action: "They are clearly a terrorist organisation.
"I note particularly that they changed their slogan in the wake of (Jo Cox's) murder to 'Death to traitors, freedom for Britain' in light of Thomas Mair's plea hearing."
Neo-Nazi Mair was handed a whole-life sentence for the murder of Labour MP Mrs Cox.
The 53-year-old shouted the words "Britain first" as he fired three shots at Mrs Cox and stabbed her 15 times in June, days before the EU referendum.
Mother-of-two Mrs Cox, 41, was arriving for a surgery in Birstall, in her West Yorkshire constituency of Batley and Spen, when she was attacked.