Greens block gay marriage twice: Labor

Labor has slammed the Greens for twice in three days blocking a Senate vote on same-sex marriage.

Opposition Senate leader Penny Wong launched a scathing attack on the minor party during a procedural motion, accusing the Greens of caring more about eliminating minor parties than eliminating discrimination against same-sex couples.

"Don't you ever come in here and tell us how committed you are to this issue," she told parliament on Thursday.

The coalition and Greens used their combined numbers to quash an attempt by Liberal Democrat David Leyonhjelm to bring on a vote of his private bill.

Greens senator Rob Simms accused Labor of using same-sex marriage as a "cheap political wedge".

"Please stop using this issue in such a cheap and cynical way, it's actually people's lives you're stuffing around with here," he told parliament.

It was a "complete and utter lie" to suggest the Greens had voted against same-sex marriage.

Senator Wong, who has two children with her female partner, was unimpressed saying she did not need to be lectured about an issue impacting people's lives.