An apprenticeship program proposed by Pauline Hanson in exchange for corporate tax cut support would cost taxpayers six times more than existing programs.
The One Nation senator claimed in March the 1000-place program had been offered in exchange for her support for the Turnbull government's corporate tax cuts.
The average cost of subsidies to apprentices under the Skilling Australians Fund is $9800, Education Department officials told a Senate estimates hearing on Thursday.
But the $60 million scheme put forward by Senator Hanson would provide $60,000 per apprentice.
Department secretary Michele Bruniges said the variation could come down to the duration of the apprenticeships.
"What, they're going to do an apprenticeship until they're 70?" Labor senator Doug Cameron asked.
Ms Bruniges said there could be variations, including from state to state, on the cost and length of various apprenticeships but she wouldn't expect such a wide variation.
Education Minister Simon Birmingham said there were no discussions with Senator Hanson, who has since withdrawn her support for corporate tax cuts, about any final proposal.
He told the committee a number of senators had raised matters with the government as they seek to pass legislation in the Senate and proposals are considered respectfully.