A brave MP has spoken out about her battle with incurable cancer.

Labor politician Peta Murphy was just 37 when she underwent a double mastectomy in 2011 after she was first diagnosed with breast cancer.

She had just been elected as the federal member for Dunkley, in Melbourne's southeast, when the cancer returned eight years later in 2019.

The re-elected MP recently switched from oral to intravenous chemotherapy, resulting in her hair falling out earlier this month.

But it will be business as usual for Ms Murphy when parliament resumes in Canberra next month, despite being one of 10,000 Australians with metastatic breast cancer.

She's now opening up about her personal experience to raise awareness and be a voice for other cancer patients who don't have a public profile.

- Constant back, bone or joint pain

- Difficulty with urinating (either incontinence or not being able to go); this can be a sign that nerves in your back are being pinched by a tumour

- Numbness or weakness anywhere in your body

- A constant dry cough

- Difficulty breathing

- Shortness of breath

- Chest pain

- Loss of appetite or weight loss

- Abdominal bloating, pain or tenderness

- Constant nausea or vomiting

- Jaundice (a yellow tinge to the skin and whites of your eyes)

- Severe headaches

- Vision problems (blurry vision, double vision, loss of vision)

- Seizures

- Loss of balance

- Confusion

Source: BreastCancer.org

'I have this unique platform of being in the Federal Parliament and, having metastatic breast cancer, I should use it to try to make life better for other people,' Ms Murphy told the Today show.

'Not everyone can keep working and do what I'm doing, but I want people to see that they're not alone, which is why I've made the decision to be so open and public about it.'

Metastatic breast cancer is an incurable condition that spreads to other parts of the body.

Australian singer Olivia Newtown-John had an off-and-on battle with metastatic breast cancer spanning three decades before she died last August aged 73.

According to statistics, the five-year survival rate for women with metastatic breast cancer is 29 per cent.

'You want people to understand that there is something happening but you don't want to be treated differently,' Ms Murphy said.

'I still want to be the best advocate I can be for my community and for people to know that who I am and what I'm doing.'

Ms Murphy's incredible story brought new Today host Sarah Abo to tears.

'That's made me a bit emotional actually, that was so beautiful ,' she said after the interview aired.

'You need stories like this to inspire those who are going through such awful times, all of us, in fact, just to get through every day - She is just incredible.

'It's so tough what people go through out there, you never know. '

Co-host Karl Stefanovic added:  It's a reminder too that we have really good people in the world and there are good people representing communities.'

Ms Murphy posted an update to her constituents on Facebook on Tuesday. 

'While my hairstyle is changing, I'm not,' she wrote.

'Yes, it means I'll be bald (won't be the only bald person in parliament!). But it also means I have the chance to be a voice for others living with the same disease.

'To make sure they know that they are seen, heard and counted.' 

While it's estimated 10,000 Australian are living with metastatic breast cancer, the exact figure isn't known because there is no register - something that Ms Murphy wants changed.

She attended Sunday night's Australian Open men's final with Prime Minister Anthony Albanese, who hailed his Labor colleague as courageous role model.

'She's also determined to overcome this health challenge by continuing to do her job, continue to work,' Mr Albanese said.

'One of the things we have to do is talk more about the complex journey of life that individuals go through and, in Peta Murphy being prepared to do that, she'll be making it easier for others.

'Peta Murphy is an inspiration for all Australians, and I've paid tribute to her courage and I wish her all of the very best.'

It's been three-and-a half years since Ms Murphy ended her emotional maiden speech in parliament by quoting children's book character Pippi Longstocking.

She found out her breast cancer had returned two weeks earlier.

'Pippi's friend Annika had just told her that she couldn't beat the strong man at the show because he's the strongest man in the world,' she said.

'"Man, yes," said Pippi, "but I'm the strongest girl in the world, remember that".'