Qantas will continue to advocate for same-sex marriage despite Immigration Minister Peter Dutton's pointed criticism of its chief executive Alan Joyce's public statements.

Key points: 20 high-profile CEOs urge Malcolm Turnbull in a letter to legislate same-sex marriage

20 high-profile CEOs urge Malcolm Turnbull in a letter to legislate same-sex marriage Peter Dutton says companies being bullied into supporting causes fearing public boycotts

Peter Dutton says companies being bullied into supporting causes fearing public boycotts Qantas says it will continue to support same-sex marriage and "other things we believe in"

Mr Joyce was one of 20 high-profile chief executives, including the heads of Westpac and Commonwealth Bank, who urged Prime Minister Malcolm Turnbull to legislate same-sex marriage earlier this week.

The letter was coordinated by the Australian Marriage Equality organisation and has been criticised by some Government ministers who argue publicly listed companies should refrain from making political statements.

Mr Dutton singled out Mr Joyce at a Queensland LNP conference on Saturday, saying he should keep his personal opinions distinct from his company platform.

"Mr Joyce is an exceptional CEO. He's a good person and I know him personally — I have no gripe against him," Mr Dutton said.

"But if he has a particular view on any issue it should be expressed as an individual."

Mr Dutton said it was unacceptable for chief executives like Mr Joyce to use their company's brand to campaign for same-sex marriage.

"It is unacceptable that people would use companies and the money of publicly listed companies to throw their weight around," he said.

"If Alan Joyce and any other CEO wants to campaign on this or any other issue in their own time and on their own dime, good luck to them.

"Don't use an iconic brand and the might of a multi-billion-dollar business on issues best left to the judgements of individuals and elected decision-makers.

"I'd prefer publicly listed companies stick to their knitting and that is delivering the services for their customers and providing a return for their shareholders."

Mr Dutton said many of Australia's largest corporations were being bullied into supporting policies by advocacy groups, fearing a public boycott of their services or products.

"Some companies are morally coerced into supporting campaigns in fear of being extorted by an online social media push to boycott their product and it is simply unconscionable," he said.

Foreign Minister Julie Bishop seemingly disagreed, and said Australia was a democracy where free speech should be protected.

"People are free to take part in public debates, and this is an issue that I'm sure will be the subject of public debate for some time," she said.

"And so, if chief executives believe that it's in the interests of their company to collaborate on a public statement, then they're free to do so."

Qantas responds, will continue supporting same-sex marriage

In a statement, a Qantas spokesman said the company would continue to express support for same-sex marriage and "other things we believe in".

"Qantas speaks out on a number of social issues from Indigenous recognition to gender diversity and marriage equality," the statement said.

"We do so because we believe these issues are about the fundamental Australian value of fairness and we're the national carrier.

"We respect the fact that not everyone agrees with marriage equality, but opinion polls show the majority of Australians do, as do many of our employees."

Business Council chief executive Jennifer Westacott also signed the public letter and said the Government needed to prioritise same-sex marriage.

"It's one of those issues we can't seem to get traction on but it's something we are asking the Government not to put off, or kick it away again," she said.

"It's something that people feel very strongly about."

Ms Westacott dismissed Mr Dutton's description of the letter as "politically correct nonsense".

"That's his opinion and we are all entitled to our views," she told the ABC on Friday.

"I know he said that business should be arguing for things like tax reform, but I don't think anyone has argued harder than I have for tax reform."