The fresh protest action marks the resumption of those tactics by the anti-Adani group, and comes after a quiet few months in which the Indian conglomerate has made few public statements while attempting to finance the project.

There are increasing signs Adani is baulking at any further financial commitment to the project while it searches for an investor. Those signs include a recent decision by Townsville council to extend negotiations over a deal to part-fund the airport. The Townsville mayor, Jenny Hill, said the deal would not be signed off until Adani “can guarantee the project will go ahead”.

Wagners has the contract to build the airport, in total worth about $30m. The activists say the financial cost of their disruption campaign would quickly cancel out any profit Wagners would make from the Adani contract.

“Any large contractor willing to threaten our future by working with Adani is bound to be targeted by citizen activists,” Galilee Blockade spokesman Ben Pennings said. “Australians clearly don’t want the Adani mine and will act decisively when governments fail to.”

“These citizens are not just disguised as superheroes, they are superheroes. Risking arrest for the wellbeing of your fellow citizens is both courageous and, seemingly, necessary.”

“It’s not acceptable for any company to threaten massive environmental damage against the will of traditional owners and the Australian people. We will disrupt and blockade Wagners’ industrial sites till they get out of bed with Adani.”

On Sunday the activists handed out flyers to Wagners staff asking for anonymous information about the Pinkenba site.

Guardian Australia has contacted Wagners for comment.