The ministry accused the party, which is led by Syarhey Kalyakin, of violating the law on political parties. It said officials suspected the party's membership was less than 1,000, the legal minimum, and accused the party of failing to provide data on its members.
The Justice Ministry's action was prompted by a request for such a probe lodged by the pro-government Communist Party of Belarus in July.
Kalyakin says the move is revenge for his party's support for Alyaksandr Milinkevich, the main opposition challenger to President Alyaksandr Lukashenka in the March election.
The poll, in which Lukashenka won re-election, was condemned by the opposition and the West as fraudulent.
Kalyakin also said the Justice Ministry's move was illegal and was aimed at preventing his party from running in forthcoming local elections.