Opposition Leader Bill Shorten says he will not be "bullied" by unions or environmental activists on Adani's Carmichael coal mine, while refusing to rule out a review of the Morrison government's decision to approve the project.

"What I will do is work with all of those interests, but I won't be the servant of any of those interests," Mr Shorten told reporters while campaigning in the Queensland town of Gladstone on Tuesday.

Bill Shorten says he will not be "bullied" on Adani. Credit:Alex Ellinghausen

"We will adhere to the science, the law, we won't create sovereign risk."

The Labor leader said he would not sign a pledge being circulated by the Construction, Forestry, Maritime, Mining and Energy Union outlining support for coal jobs because, unlike his candidate for the local seat of Flynn - Zac Beers, who has signed - "I'm running for Prime Minister".