Supporters on both sides of politics are at odds with their parties on some key issues including the environment, asylum-seekers and counter-terrorism legislation, Fairfax Media's YourVote survey has revealed.

With the survey completed by about 162,000 Australians on Fairfax Media news websites, YourVote has found strong support for same-sex marriage, climate action and a crackdown on multinational tax avoidance.

It has also revealed backing for medically assisted dying for the terminally ill and protection of the Great Barrier Reef.