The Greens are demanding an explanation from Clive Palmer about an apparent alliance with the Australian Sports Party's senator-elect Wayne Dropulich.

Fairfax Media reported on Tuesday that Mr Dropulich, who won a senate seat after the controversial recount in Western Australia, has been wooed by Mr Palmer's United Party and could join a senate voting bloc.

Clive Palmer greets Sports Party senator-elect Wayne Dropulich after he addressed the National Press Club in Canberra on Tuesday. Credit:Andrew Meares

Mr Dropulich, a veteran gridiron player, is expected to attend Mr Palmer's speech to the National Press Club in Canberra on Tuesday, along with Australian Motoring Enthusiasts Party senator-elect Ricky Muir.