The relegation of Tasmanian Labor Senator Lisa Singh to the unwinnable fourth spot on Tasmania's Labor Party ticket for the next election is poor electoral strategy, says former Queensland Labor senator Margaret Reynolds.

Australian Manufacturing Workers Union secretary John Short leapfrogged the sitting Senator to take third spot, with federal leader Bill Shorten refusing to intervene.

Ms Reynolds said the decision was poor electoral strategy and should be overruled by the national party executive.

"It doesn't make sense when you're trying to maximise your Senate vote to drop one of your best known senators to an unwinnable position," she said.

She added: "They can't afford to deny young talented women the opportunity to continue in their role."

Senator Singh, 42, is not aligned to any faction at the state level, where the decision was made, but enjoys the support of powerful federal colleagues.

In 2010, then prime minister Kevin Rudd intervened in the state's preselection process to dump union boss Kevin Harkins from the ticket in favour of Senator Singh.

She appears not to enjoy the same support from Mr Shorten, who declared at the Tasmanian annual ALP conference on Saturday that "the rank and file have spoken".

'I'm a reasonable candidate': John Short

John Short, the man who overtook Lisa Singh on the ticket, said the preselection ballot was fair.

"It's a very democratic process," he said.

"In fact, the Tasmanian branch has got the most democratic process of any branch in Australia."

He maintained that he was a worthy replacement.

"I think I'm a reasonable candidate because I've got a lot of life experience," he said.

"I've done a lot in my life, brought up a family, struggled at times, and I know what it's like to struggle, and I stand up for workers every day."

Senator Singh has two years of her term to serve.