Bill Shorten has repeatedly denied that he told colleagues he intended to ban the Adani coal mine, but dodged questions about whether he intended to revoke its licence if Labor wins the next election.

Shorten was asked on Friday to clarify Labor’s position after the businessman and environmentalist Geoff Cousins this week gave a detailed account of private discussions he had with the Labor leader over December and January.

Cousins said that after a tour of the Great Barrier Reef and the Adani mine site in January, Shorten signalled his support for Labor revoking Adani’s licence based on concern about the impact of the project on the reef, on groundwater and endangered species. He then indicated he would make an announcement to that effect imminently.

Geoff Cousins reveals how Bill Shorten wavered on Adani mine Read more

The Labor leader faced questions while campaigning in Devonport on Friday ahead of the Tasmanian election on Saturday, including whether he was prepared to announce Labor would revoke the project’s licence if it won government.

Shorten denied on Friday that he wanted to ban the project, and had to be talked out of that position by colleagues.

But the Labor leader did signal publicly after his trip with Cousins, without locking in to a specific option, that he was intending to adopt a harder line against the controversial Queensland coal project.

Shorten also made it clear internally following his discussions with the former president of the Australian Conservation Foundation that he wanted to toughen Labor’s position on Adani, and explore options within the Environment Protection and Biodiversity Conservation Act for stopping or limiting the project.

Labor’s pivot on Adani went for discussion to shadow cabinet in early February.

Guardian Australia has been reporting since January that there are a range of internal views about how hard to go – and some players, including the CFMEU and the frontbencher Anthony Albanese, have argued publicly against stopping a project which has already been through environmental approvals.

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Some Labor figures have been worried about triggering a backlash about sovereign risk, others about the political impact in Queensland. Some who are opposed to the project are concerned there is not a clear legal pathway to that policy.

Legal advice supplied by Cousins and the ACF is considered by some Labor figures to be overly optimistic.

Cousins’s comments have been deeply embarrassing for Shorten and uncomfortable for the ALP given the party is currently facing off against the Greens in the Batman byelection in Melbourne.

Shorten on Friday said he’d made no secret of the fact he wasn’t a fan of the Adani project.

“But what I’ve also said – and I’ve also said it to the Australian Conservation Foundation and right through Queensland – is I respect the principle of Australian politics that if one government enters into contracts then a future government can’t simply rip them up. To do so would be sovereign risk.”

Shorten said he did not believe the project would materialise, citing Adani missing deadlines and his assessment that the project didn’t stack up “financially, commercially, or environmentally”.

Shorten denied that he wanted to ban the project and had to be talked out of that position by colleagues. “You can’t simply ban it and create a sovereign risk ... No party, even the Greens political party, can simply say they can ban something – you have to adhere to the law.”

Asked if he had said – at any stage – that he wanted to revoke the licence of the Adani mine, Shorten said: “No prime minister can simply ignore the law, no prime minister worth their salt should simply engage in massive sovereign risk.”

Shorten said Adani had become “ground zero for a whole lot of other arguments” and accused others of “dumbing down the debate about climate change and the future of mining to one mine project”.