The ultra-nationalists parties at the European Parliament, including the British National Party, could be barred from receiving around £330,000 worth of funding from the EU, if around 70 more MEPs support a change in the funding rules.
The cash, which is due to be awarded in a fortnight, , is the subject of a campaign by British anti-fascist movement Hope Not Hate, who are trying to get MEPs to block far-right groups in The Alliance of European National Movements from being granted the money.
Parties in that group include the BNP, Hungary's Jobbik party and France's Front National.
The group received €300,000 in 2012, prompting calls that they be banned from future funding from tax-payers.
The petition has also been backed by several MPs like Ian Austin and Tom Watson.
In September 2012, European Commission Vice-President Maroš Šefcovic announced new rules for the funding of pan-European political parties to ensure that EU money was only given to parties and foundations that observe the values of the EU, "namely respect for human dignity, freedom, democracy, equality, the rule of law and respect for human rights, including the rights of persons belonging to minorities".
For the new rules to be adopted, a quarter of MEPs must vote to enforce the rule. Hope Not Hate's director Nick Lowles told The Huffington Post UK that 119 MEPs had agreed to support the new Rule 210, but 70 more were still needed.
All of Labour's 13 MEPs have agreed to back the new rules and around 2,300 people have now signed the petition.
Lowles said in a statement: "It is preposterous that public money can be used to incite racism and hatred. But time is short."
But some on social media called out the rules as anti-democratic, as the BNP, represented by leader Nick Griffin, are elected representatives to the EU.