Australian authorities have warned of possible violence during Thailand's national elections, urging travellers to exercise a high degree of caution due to potential civil unrest.

Thailand's voters go to the polls today, with the main opposition Pheu Thai Party hoping to snatch power from the incumbent Democrats.

The election comes after 2010's series of bloody and violent anti-government protests which left more than 80 civilians dead and many more injured.

Australia's Department of Foreign Affairs and Trade has updated its advice for travellers heading to Thailand, warning of possible violence, terror attacks and unrest.

New Zealand's Ministry of Foreign Affairs and Trade reviewed its advice two weeks ago, saying there is some risk to people's safety in Bangkok and other areas due to the uncertain political situation.