Attorney-General George Brandis has ruled out suspending anti-discrimination laws during the same-sex marriage plebiscite campaign.

The Australian Christian Lobby - which has been among the most vocal opponents to same sex marriage - in February called for the federal government to "override" laws that prohibit discrimination on the basis of sexuality during the campaign, which is expected to take place after the election. Its managing director Lyle Shelton has said this would ensure the "no" campaigners could speak freely without being threatened by legal action.

Attorney-General George Brandis says he doesn't think anti-discrimination laws should be suspended during the same-sex marriage plebiscite campaign. Credit:Andrew Meares

Greens senator Robert Simms referred to the proposal during Senate estimates on Thursday as designed to "facilitate a hate campaign".

Senator Brandis rejected this, saying "that's, I'm sure, not their purpose", but said he did not think the laws should be suspended and later ruled out doing so.