Peter Dutton is staring down fierce criticism from "crazy lefties" as he pushes on with plans to bring white South African farmers into Australia.

The Home Affairs Minister insists he is unperturbed by "mean cartoons" and negative media coverage.

"They don't realise how completely dead they are to me," Mr Dutton told 2GB radio on Thursday.

"We just get on with making decisions that we need to."

Mr Dutton caused widespread controversy and diplomatic tensions after arguing last week the "persecuted" farmers needed help from a "civilised country" like Australia.

He wants the farmers fast-tracked through Australia's refugee program.

Related reading South Africa demands Dutton retracts 'persecuted' white farmers comments

Greens senator Nick McKim labelled the minister a racist and fascist, arguing the Liberal Party was still wedded to the White Australia policy.

"It's naked and it's transparent and it's out in the open," Senator McKim told Sky News.

Senator McKim said it was plain Australia's immigration settings under the Turnbull government were race-based, pointing out there were no white people being held in offshore detention.

"I can be absolutely certain that if a South African person arrived by boat to seek asylum in Australia they would not end up on Manus Island and Nauru under Peter Dutton's regime," he said.

Mr Dutton insists he is blind to skin colour and will continue to bring in migrants based on the national interest.

"It concerns me that people are being persecuted at the moment - that's the reality - the numbers of people dying or being savagely attacked in South Africa is a reality," he said.

Mr Dutton likened the latest backlash to reaction over his comments about a supposed African gang crisis in Melbourne over summer.

"Stick to the facts and you're on safe grounds so all of the criticism over the last week has meant nothing to me," he said.

Mr Dutton said he had been inundated with messages of support and references to particular cases of white South African farmers in need of help.

"We'll start to work through those and if people meet the criteria under the program then they'll settle under the program here," he said.

"If people think I'm going to cower or take a backward step because of their nonsense, fabricated, fake news criticism, then they've got another thing coming."

Meanwhile, one of his coalition colleagues is warning there could be food shortages if white South African farmers are allowed to migrate to Australia.

"The black South African farmers certainly have not proved themselves," Nationals MP Andrew Broad told ABC radio.

"They need the skill set of the white South African farmers if they're going to have any chance of feeding the population that they've got."

Mr Broad, who travelled to the country several years ago, urged other MPs to visit and see for themselves.

"We'd be better to be working with the South African government to make them value those white farmers, rather than trying to help them flee," he said.