A new political fact-checking website has launched with lofty plans to keep politicians honest and voters better informed.

PolitiFact Australia says it will fact-check claims by MPs, parties, candidates and other influential figures.

Tony Abbott and Julia Gillard. Credit:Andrew Meares

The website is the first international affiliate of Pulitzer prize-winning US site, PolitiFact.

It will rate political statements as true, mostly true, half true, mostly false and false. The US website calls this scale "Truth-O-Meter".