Kerryn Phelps, a leading independent candidate for the upcoming Wentworth byelection, has formally recommended her supporters put her Liberals rival Dave Sharma ahead of Labor's Tim Murray.

Releasing her how-to-vote card as postal voting began in the waterside eastern Sydney electorate on Tuesday, Dr Phelps placed both of the main parties way down the list at 10 and 11, respectively, out of 16 candidates.

Kerry Phelps, an independent candidate for Wentworth, has revealed her preference priorities. Credit:James Brickwood

The former head of the Australian Medical Association preferenced Kay Dunne, the Sustainable Australia candidate in the second slot and Ben Forsyth, from Senator Darryn Hinch's Justice Party in third.

Dr Phelps' preferencing has drawn criticism from some voters who see her positions on issues such as climate action as more closely aligned with Labor's than the Liberal Party she is giving a higher ranking on her vote cards.