Senior executives at the world’s largest insurance broker, Marsh, will meet in the US this week to decide a new global position on coal projects, including whether to continue support for the Adani Carmichael coalmine.

Marsh has come under pressure, in Australia and overseas, due to its work as a broker for the controversial Adani coal and rail project in north Queensland.

Guardian Australia understands Marsh had been attempting to arrange insurance coverage for elements of Carmichael, after many of the world’s top-tier insurers publicly said they would not underwrite the project.

Environmental and activist groups seeking to stop the Adani project have in recent months focused significant efforts on the insurance industry. John Quiggin, a professor of economics at the University of Queensland, has said the Carmichael project “can’t proceed” without insurance.

On Tuesday, Australian employees of Marsh attended a town hall-style meeting in Melbourne. When asked about pressures on Marsh from activist groups in relation to its work for Adani, Marsh Pacific chief executive Nick Harris defended the broker’s involvement in coal projects.

But Harris told staff the company’s top global executives had come under pressure and would be meeting in New York on Thursday “to formulate a position on this”.

He said the company had received “a lot of input” from Australia and elsewhere, including from clients who had urged Marsh to come up with a definitive stance.

It is understood the meeting this week will involve John Doyle, the Marsh chief executive, and Dan Glaser, the chief executive and chairman of parent company Marsh and McLennan.

Glaser has previously spoken about how climate change is among the biggest risks to the insurance industry.

Peter Bossard from the unfriend coal campaign said the global insurance industry was rapidly shifting away from coal and that Marsh “needs to join this trend”.

“Only the most reckless companies will touch the Adani coalmine at this point, and climate campaigners will relentlessly target Marsh’s reputation and mobilise shareholders at its upcoming AGM (in New York in May) if the broker gives the project a new lease of life.”

Adani says its insurance provider details for Carmichael are commercial in confidence, but insists it has “the requisite insurance requirements in place”.

However the ongoing involvement of a brokerage firm indicates there are elements of the Carmichael project that still require underwriting in the long term. Late last year, a series of large international insurers ended contracts with Adani or ruled out insuring its coalmine.

AXA, a French insurer, had an agreement to “partly cover the [Adani] railway asset” until this year. AXA has said it won’t renew that contract, leaving Adani to seek alternate arrangements.

Two other insurers that could have provided coverage, Axis Capital and Canopius Group, both said they would not underwrite elements of Carmichael.