Lambie proposes triple treat plebiscite

Money could be saved by having a same-sex marriage plebiscite on the same day as a referendum on constitutional recognition of indigenous Australians, as well as euthanasia for the terminally ill, a crossbench senator says.

Independent Jacqui Lambie cites Parliamentary Budget Office advice she's received showing all three could be done for the price of two.

"Why can't we leave it until about September next year," she asked reporters in Canberra on Tuesday.