Malcolm Turnbull's constituents and those of six of his senior ministers overwhelmingly oppose taxpayers subsidising the planned Adani coal mine in Queensland.

Polling conducted by ReachTEL for the left-leaning think tank The Australia Institute also finds more voters support a ban on new coal mines than would oppose one.

The government's Northern Australia Infrastructure Facility is considering whether to grant Indian company Adani a $900 million loan to build a rail line to its planned Carmichael coal mine.

Pollsters surveyed people in Wentworth (Mr Turnbull's seat), Cook (Scott Morrison), Curtin (Julie Bishop), Dickson (Peter Dutton), Flinders (Greg Hunt), Kooyong (Josh Frydenberg) and Sturt (Christopher Pyne).

Results showed on average 62.5 per cent opposed any government loan for the rail link, with opposition strongest among voters in Treasurer Scott Morrison's southern Sydney seat.

Fewer than one in four people were in favour of a loan, with support highest among voters in Mr Dutton's Brisbane electorate, the only Queensland seat surveyed.

There were similar results on the question of whether taxpayers should be subsidising the Adani mine in any way.

Australia Institute executive director Ben Oquist said it made sense the Liberal Party base would oppose subsidising an industry as well established as coal mining.

"Despite a push by some conservatives for coal subsidy polices, these results - in key blue-ribbon Liberal seats - show strong opposition to that very idea," he said on Monday.

"These results show that Malcolm Turnbull should be confident in staring down the pro-coal faction in his party room."

Voters were also asked if they supported or opposed a moratorium on building coal mines, meaning existing mines could continue running but no new ones would be allowed.

More people thought a moratorium was a good idea than not, but the suggestions only got a majority of support among Mr Turnbull's constituents and those in Energy Minister Josh Frydenberg's inner-Melbourne seat.

But almost one in four people responded they didn't know where they stood on the moratorium.