US Presidential hopeful Ted Cruz has been pulled up by the Washington Post for telling some "whopper" tales about Australia, gun control and crime.

Cruz reckons that since Australia's 1996 gun buyback program, "the rate of sexual assaults, the rate of rapes, went up significantly, because women were unable to defend themselves."

Analysis by the Washington Post shows while the rate of sexual assaults in Australia increased slightly between 1996 and 2014, "there was no significant spike or drop after the 1996 legislative changes or buyback program".

"The increase likely is affected by the increase in reporting, and there wasn’t prevalent use of handguns for self-defense before 1996, as Cruz suggests," they wrote.

The WaPo also points out, correctly, there was no blanket exemption allowing people to use handguns for self-defence before the Howard Government introduced gun control legislation.

There also hasn't been a mass shooting in Australia since the gun buy back.

The newspaper, which once brought down a president, graded the presidential hopeful with four Pinocchios -- a whopper.