Treasurer Jim Chalmers would have known his department was going to recommend revamping the stage three tax cuts when he requested it to come up with new options on cost-of-living relief, Treasury secretary Steven Kennedy has suggested.

Appearing before a Senate estimates committee on Tuesday, Dr Kennedy said when Dr Chalmers asked him on December 11 to come up with new policy options, “I think outlined in broad terms that there were not going to be many opportunities to do that without looking at the tax system”.