The Turnbull government has ditched its offer to spend $4 million on a research centre to be headed by "sceptical environmentalist" Bjorn Lomborg.

Education Minister Simon Birmingham said on Wednesday that the government had taken the offer off the table.

"A specific incentive for the government for such an institute is no longer available," Senator Birmingham told Senate estimates hearings on Wednesday.

Senator Birmingham said his predecessor, Christopher Pyne, had decided in his last week in the job that the project was "unlikely to enjoy success and that the funds could be better utilised elsewhere".