The controversial senator who Prime Minister Scott Morrison has attacked as a "repeat offender" on racism used taxpayer funds to fly to at least three far-right meetings across Australia.

Fraser Anning, whose attendance at a rally organised by convicted extremist Blair Cottrell at St Kilda on the weekend unleashed a wave of angry criticism, also billed taxpayers to appear at other events in Sydney and Melbourne, bringing the combined cost of his three trips to nearly $10,000.

Mr Morrison attacked the Queensland senator on Monday for associating with "extreme and offensive racist views" and backed calls for the former One Nation figure to consider his future in Parliament.

Senator Anning is under fire after charging taxpayers more than $2800 for return flights to St Kilda, where some protesters were seen performing Nazi salutes at the rally organised by Mr Cottrell and Neil Erikson, far-right nationalists who have been previously convicted of inciting serious contempt for Muslims.