The Electoral Commission has agreed to re-register United Future as a political party.
The party was forced to de-register on 31 May this year because it couldn't guarantee that it had 500 paid-up members.
Following checks of submitted membership forms, the commission said on Tuesday it will restore United Future to its official register from 15 August.
United Future had hoped to have been re-registered much sooner, but the commission refused to accept an electronic spreadsheet of member details.
Party leader Peter Dunne said he is very pleased the commission has finally made a decision, and will seek to have Speaker of the House David Carter recognise United Future as a Parliamentary party.
When United Future was de-registered, Parliament no longer recognised him as a party leader, which meant he lost funding.
Peter Dunne said he is drafting a members' bill to reform what he called a cumbersome registration process.
"This situation has thrown up a number of anomalies in the current electoral law that need to be amended.
"I'm proposing a bill that will firstly provide for online party memberships to be accepted for registration purposes - the idea that we had to have quill pen and parchment signatures is simply out of date in today's environment."
Mr Dunne said political parties should be made to undergo membership audits every three years.
Prime Minister John Key welcomed the Electoral Commission's decision to re-register United Future and signalled that the Government was likely to support Mr Dunne's move to change the rules for party registrations.