Clive Palmer has been overheard questioning the intelligence of outspoken Palmer United Party Senator Jacqui Lambie, in a conversation with colleague Zhenya "Dio" Wang at Parliament on Tuesday, according to sources.

It comes as cracks emerge within the minor party particularly over Senator Lambie's inflammatory comments on Islamic law, which she claimed "involves terrorism".

But in a bizarre twist, Senator Lambie's media adviser emailed her response to questions from Fairfax Media to all journalists in the Parliamentary press gallery, in which she denied her leader said she was "not very bright" and inisisted that Mr Palmer had instead made those comments about her colleague Senator Wang.