An Australian country music icon has called out One Nation leader Pauline Hanson and reignited debate about Australia's national identity.

John Williamson, 80, posted two handwritten letters on social media questioning the senator's 'True Blue' status, despite her party's recent surge in the polls.

The first letter ridiculed Hanson's longstanding anti-immigration stance and included a reference to her pre-politics career running a fish and chip shop.

'As someone who has stayed in country towns for 56 years, I have to say that dinners before the show have improved out of sight,' the Aussie music legend wrote.

'Even your fish 'n' chip shop concept was brought here by the Greeks.

'In Sydney, there would not be one restaurant we know that is not owned or served by those you seem to despise.

'What are you holding on to? None of us really own Australia. We simply earn the privilege to be a part of it.'

In his second letter, the ARIA hall-of-famer and 28-time Golden Guitar winner hit back at Hanson's defence of the Australian flag and proposed an alternative design. 

The proposed flag featured the Southern Cross and a yellow kangaroo on a red background, with the Union Jack conspicuously absent.

'Hi again Pauline, you are really bothered by the fact we seem to have two or three flags representing our country,' Williamson wrote.

'I am bothered by that too. So why don't we have a flag that brings us all together? The current National British ensign that racists wrap themselves in surely doesn't do the job.'

It sparked almost 9,000 comments from Aussies with mixed feelings about the post. 

'What a legend John Williamson is,' one wrote on X.

'Australia is multicultural and proud for everyone who calls Australia home. We are all Australians, no matter where we come from. 

'Fight the ONP propaganda wherever you see it friends. Australia never was and never will be about hate.'

Another added: 'Thank you John for your very simple but accurate take on just one of the ways migrants have improved Australia.'

A third wrote: 'Thank you, Sir, for opening the eyes of those who were ready to see. Who knows what colours the rainbow holds for the rest of them.'

But many others leapt to Hanson's defence and accused him of missing the point of her policies.

'She is fighting for our culture, which you have celebrated and made a living from your whole life,' another commented. 

'It deserves some respect, and there is nothing wrong with that. Doesn't mean we can't celebrate other cultures, just in Australia, our culture has to come first.'

Another added: 'Somewhat out of touch from a man who made his money from Aussies buying his music.

'A true Aussie is either born here or from an immigrant family that did all the hard yakka like building the rail networks, water pipelines, etc, and integrated into an Aussie way of life.'

Others suggested that Williamson stick to music.

'Start talking to those people in the country towns. I'm sure that their opinion of Pauline differs considerably to yours!' one wrote.

Another added: 'Hey John, looks like you may have failed the pub test - read the room, the tribe has spoken!'

A prominent supporter of the 'Yes' campaign for the Australian Indigenous Voice referendum, Williamson slammed the use of his signature song, 'True Blue', at March for Australia rallies across the nation last October. 

'True Blue is a song for all Australians and should not be hijacked by any group that seeks to use the song to sow division,' he said at the time.

'I believe in a multicultural society – one where all Australians come together in unity to celebrate our unique multicultural nature and freedoms.'

Williamson announced in January that his performance at the annual Tamworth Country Music Festival would be his last, after 56 years in the industry.

'I'll keep writing songs. I still love writing songs and I still love playing, but I really am over being on the road,' he said.

'I've got a lot of things I want to do – I'm 80 now – and I want to do it before I drop dead.' 

Williamson burst onto the country music scene back in 1970 with the novelty song Old Man Emu, which won him first place on TV talent quest New Faces.

He parlayed that early win into a formidable career that has, so far, seen him release 21 studio albums.

A fixture of the Tamworth Country Music Festival, Williamson has also picked up an impressive 28 Golden Guitars and, in 1992, was made a Member of the Order of Australia for services to music.

The announcement comes after John recently performed his iconic song True Blue at the third Ashes Test at Adelaide Oval last December, three days after the Bondi terrorist attack that claimed 15 lives.