Shorten's captain's call was bad timing

Labor leader Bill Shorten has backed down from his ‘captain’s call’ to roll back company tax cuts for businesses with turnovers between $10 million and $50 million a year, after a leadership meeting today.

Mr Shorten was in the middle of a press conference this week when he was asked if he would roll back tax cuts for companies with turnovers from $10 million to $50 million a year.

"Yes," he said.

It was a shock to his frontbench, whose thinking had been heading in that direction but no formal decision had been made.

Tasmanian Labor backbencher Ross Hart called up a local radio station on Wednesday and unprompted - twice - called it a "captain's call".

It sparked a testy partial back down on Friday.

Many small and medium businesses are already operating under the lower tax environment, meaning Shorten's decision would have hiked their taxes from next year.

"I now accept that simply stopping at $10 million would have created more confusion and uncertainty and it was not the main game," Mr Shorten told reporters.

The captain's call came at an awkward time for the Labor leader, the second time this year he's faced difficult policy questions while campaigning in by-elections.

In March, Shorten was being wedged over Labor's support for the Adani coal mine as he tried to win the Batman by-election against the Greens.

This time there are two key by-elections, and vague leadership rumblings, while Shorten told businesses and their workers he planned to hike their taxes.

Malcolm Turnbull certainly didn't waste any time.

"I look forward to the leader of the opposition's tip-toeing through all the land mines he's created around Australia," the prime minister told parliament.

"Every business knows that Labor is a threat, it's a threat to the business, it's a threat to the employees."

Labor will win the seats it holds in Perth and Fremantle, but Queensland's Longman and Tasmania's Braddon are knife-edge.