The United Future party has made a statutory declaration to the Electoral Commission to be re-registered as a political party.
On 31 May the party asked to be formally deregistered because it could not guarantee it had 500 paid-up members.
United Future president Robin Gunston said on Tuesday the party has seen a surge in renewals and new members in the past week despite the resignation of leader Peter Dunne as a government minister.
Mr Dunne has refused to co-operate with an inquiry into who leaked a report into the Government's spy agency.
The Electoral Commission must treat United Future's re-registration the same as for a new party, which involves a random check of the membership details provided.
It could be several weeks before the party is officially re-registered.