John Swinney wants to overhaul the SNP system

The changes involve one-member-one-vote selection of the SNP's leader and parliamentary candidates.

John Swinney promised reform after he crushed a challenge to his leadership in the autumn and said it was time to change the party's "cumbersome" system.

Under his proposals, the SNP's main goal would also be switched from "self-government" to full independence.

Mr Swinney wants to rewrite the entire constitution, meaning the leader and deputy leader would be elected by the membership as a whole, not the party conference.

Instead of a single branch nomination, challengers would need support from 100 members across 20 branches.

I think the SNP has to reach out to a wider proportion of our membership SNP leader John Swinney

The leader would appoint a new business convener to chair the party's executive and run its headquarters.

Candidates would also be chosen by the broad membership, rather than branch hustings, with a stated aim for gender balance among candidates.

Underpinning SNP policy would be the aim of full Scottish independence instead of "self government", which some have regarded as ambiguous.

Speaking on BBC Radio's Good Morning Scotland programme, Mr Swinney said it was time to change the SNP's constitution after 40 years.

He said party members had been consulted on the proposed changes over the past few months and would have the opportunity to vote on them at a party conference in April.

'Policy and direction'

The SNP leader said he was confident the proposals would receive widespread support and represented the way in which members wanted the party to progress.

Mr Swinney said Nationalists would be able to concentrate on the campaign for independence rather than the "cumbersome, internal business that often preoccupies us".

"I think the SNP has to reach out to a wider proportion of our membership and involve them directly in the business of the party," he said.

Alex Neil (left) said recruiting more women could be difficult

"It's happening in the election of the leader and deputy leader and also in the ranking and selection of parliamentary candidates at all levels.

"Setting the policy and the direction of the party will continue to be resolved by our conference and our national council to make sure our activists are fully involved in deciding the direction of the party."

Mr Swinney said he wanted SNP members to tell him if they would be happy with "a mechanism" to ensure gender balance.

"It's an issue I think we have to confront as a party and we need to have consensus," he said.

The problem within the party has not been an unwillingness to elect women but that we don't have enough women members Alex Neil, SNP MSP

"I think it's time we had such a mechanism to ensure our parliamentary group is representative."

Alex Neil, SNP MSP for Central Scotland, said while moving to one-member-one-vote was "inevitable", any attempt to encourage more women into politics would prove more difficult.

He said: "We all share the aspiration of getting many more women into the parliamentary party.

"The problem within the party has not been an unwillingness to elect women but that we don't have enough women members.

"Quite frankly, constitutions don't solve that problem."

Mr Neil said he believed women in Scottish society, generally, gave priority to family rather than politics.

'Desperate move'

"The party has to do something to increase the number of women members and the number of women who are prepared to be activists," he said.

Meanwhile, Labour claimed the changes were designed to make it harder for the party to drop Mr Swinney as leader.

Scotland Office minister Anne McGuire said: "The truth behind this constitution is that John Swinney fears he can't remain leader for much longer and is desperately trying to hang onto his job.