The Labor Party has suspended right-wing MP and president of the upper house, Amanda Fazio, after she crossed the floor on a bill dealing with the sale of pornography.

Under party rules, MPs must vote along party lines, except if they are allowed a conscience vote.

During a debate in Parliament last night, Ms Fazio defied her party by crossing the floor to vote with the Greens. She has yet to explain why.

The bill is designed to boost the powers of police on the sale of X-rated material.