Former Labor premier and foreign minister Bob Carr says the ALP should be focusing on ethos and leadership, rather than structure, to restore support.

Bob Carr reckons a ramshackle old party like Labor should just make it up as it goes along if it wants to win back voters.

On the day federal leader Bill Shorten outlined sweeping reforms for a more democratic ALP, his former cabinet colleague was suggesting something more simple – crafty leadership, winning speeches and punchy one-liners to lift its spirits as well as directing scorn at its opponents.

Mr Carr, Labor’s longest-serving premier in NSW and foreign minister in the Gillard and Rudd governments, acknowledges the party could tinker with its structure.

But like the conservative parties, the ALP was improvised and cobbled together, he said.

A different approach was to focus on ethos and leadership.

He used the leadership record of another NSW premier, the late Neville Wran, to make his point.

“Making it up as you go along if it’s done with flair, intelligence, and if it’s entertaining,” he said on Tuesday.

Mr Shorten believes a more prescriptive formula is needed to make Labor a modern, outward-looking, confident and democratic party.

He has set an ambitious target of 100,000 members – more than double the current number.

To achieve that figure he has asked the party to look at online membership applications that will take minutes, not months, to approve.

The compulsory requirement to join a trade union will be dropped and a fee structure introduced to attract those on low incomes.

The rank and file will have a weighted vote in the pre-selection of lower house candidates, and a “meaningful say” for Senate contests.

But a political historian warns measures to curb the influence and power of trade unions comes with some risk.

David Burchell, from the University of Western Sydney, says Labor is “poor as a church mouse” and must tread carefully if it wants to enjoy the continued financial support of unions.

He also questions whether the flagged changes will matter where it really counts – at the ballot box.

“Labor’s primary vote has hit parlous depths and it’s not really budging,” Dr Burchell said.

Because ALP members tended to hold views left of the wider community, giving them a greater say arguably could make the party’s position worse.

Mr Shorten admitted he had not sought the support of particular unions for his move to drop compulsory membership.

“I think that rule has outlived its day,” he said, adding Labor had to broaden its image beyond the union movement.

Queensland Council of Unions president John Battams warns Australians will suffer if the trade union movement lost influence in the political process.

But he agreed with measures to make party membership easier and cheaper to obtain.

Mr Battams played down the role unions and factions enjoyed in Senate pre-selections races that threw up people like Joe Bullock who headed Labor’s ticket for the West Australian election re-run.

“All political parties have dud candidates from time to time,” he told Sky News.