Greens policies will be costed twice by the Parliamentary Budget Office and publicly released before the September 7 election, Greens Senator Larissa Waters insisted on Thursday.

Senator Waters was replying to accusations from Opposition Leader Tony Abbott that the Greens had "fringe economic policies" and were economically irresponsible.

She questioned whether the Opposition would follow the Greens' lead and send its policies back to the non-partisan PBO to be costed again before the election.

"Mr Abbott ... has the audacity to say that other parties are not economically responsible," Senator Waters said.

"That is a bit ridiculous when he is the one who has sadly not submitted his policies again to the PBO," she said.