Same-sex marriage will give rise to polygamy - Pauline Hanson

Controversial Australian senator Pauline Hanson says she doesn't want same-sex marriage legalised because it will lead to polygamy and more youthful marriage down the track.

Ms Hanson, who is well-known for her controversial stance on a number of issues, also filed an amendment to the same-sex marriage bill that would allow wedding celebrants to refuse to marry someone on religious grounds.

Speaking to the senate on Tuesday, Ms Hanson explained her stance on gay marriage and took issue with people's inability to "have an opinion and have a say in this country".

"My concern is that in time to come, the parliament and its members could at any time change to include multiple marriages or marriages of people under a certain age," she said.

"I don't believe that will be the will of the people. If it was a referendum it would be enshrined in the constitution and cannot be changed by parliament but only by the people."

The so-called 'slippery slope' argument employed by Ms Hanson is one commonly used by those who oppose same-sex marriage, but there is not much evidence to support it.

Australia would be the first nation to legalise polygamy after first legalising gay marriage, if Ms Hanson's fears are ever realised.

Ms Hanson also said gay marriage would have a negative impact on the children of same-sex couples.

"What do we do as a society when we get to a stage when these kids are going to school and... the teacher says 'I want you to draw a picture of your Mum and Dad or Grandma and Grandad'?" she asked.

"So the kid is there saying, 'What am I going to do? I don't have a mum or a dad - it's Peter and Sam', 'it's Elizabeth and Amanda'. They're not known as Mum and Dad."

Ms Hanson drew ire earlier this month when she claimed Australian children were being taught how to masturbate and strap on sex toys in their sex education classes.