The far-right British National Party could be fined because it failed to file its annual accounts with the elections watchdog, it has emerged.
An Electoral Commission spokesman said the BNP should have handed over its financial details by 7 July.
The party was given an extension to the end of July but failed to meet that.
The commission is currently considering reporting the offence to the police which could lead to the BNP being fined up to £5,000.
An Electoral Commission spokeswoman said: "Our commissioners are now considering what action, if any, to take."
Last month Barclays froze up to 20 BNP accounts held with the bank.
The party said it would take legal action over the issue.