The Democratic Labour Party has been deregistered ahead of the federal election due in May.
The Australian Electoral Commission said the party did not meet the requirements of registration, including having at least 1500 members or federal parliamentary representation.
A membership list lodged by the party in December contained the details of 1650 people.
But subsequent checks by the AEC found a number of duplicate names, some names that could not be matched to the electoral roll and 21 people on the list who were dead.
A further random sample check found 14 people who denied membership - well above the four denials of membership permitted under electoral laws.
The party argued the AEC's processes were flawed but the decision was upheld.
The DLP was formed in 1955 as a result of the ALP split and was represented in the Senate from that year until 1974.
It returned to prominence in 2010 with the election to the Senate of John Madigan, based on a primary vote in Victoria of 2.3 per cent.
He left the party in 2014 to sit as an independent but failed to get re-elected at the 2016 double dissolution election after forming his own party.
Mr Madigan died in June 2020.
