Attorney-General George Brandis's amendments to the Racial Discrimination Act will open the floodgates for racists and bigots to dominate the public debate, say the Australian Greens.

"This is the Andrew Bolt Protection Bill - the Attorney General is looking out for his mate but has spared no thought to those who are the victims of racial abuse," Australian Greens spokesperson for Legal Affairs Senator Wright said.

The Australian Greens have renewed calls for Attorney-General George Brandis to drop his bid to amend the Racial Discrimination Act, following the minister's responses in Question Time today.

Australian Greens spokesperson for legal affairs Senator Penny Wright today asked the Attorney-General why he would not reconsider in light of concerns raised by Liberal MP Ken Wyatt.

South Australian Greens Senators Sarah Hanson-Young and Penny Wright have expressed their sympathies for the families that will be affected by Holden's closure and have called for the development of a sustainable manufacturing future for the state.

"The Greens are calling for a multi-party, multi-stakeholder summit to develop a sustainable manufacturing future for South Australia," Senator Hanson-Young said.

The Australian Greens have today backed calls by a coalition of ethnic and indigenous groups to protect laws against racially-motivated hate speech, saying the Coalition’s plan to weaken protections against racism is shameful.

“The Greens will never support any moves that make it easier to abuse people on the basis of race,” said Senator Richard Di Natale, Greens spokesperson for Multiculturalism.

“Multiculturalism is one of Australia’s greatest success stories but racial vilification is still a reality for too many people in our society.