Katarina Anderson, 62, applied for a compassionate exemption to travel to Melbourne more than three weeks ago.
Her daughter Georgie, 33, has been diagnosed with an advanced form of breast cancer. She began chemotherapy on July 29.
Ms Anderson is fully vaccinated with AstraZeneca and willing to pay for her own two week hotel quarantine.
She’s tested negative to COVID-19 four times since July 19.
“I believe I am the only solution to help my daughter and her family cope through this devastating set of circumstances”, her request read.
On Friday, Ms Anderson’s request was denied.
“I was devastated,” she told Sky News Australia.
“It’s the most frustrating thing. Having your daughter and the kids in that situation and I’m wanting to be emotionally, physically helpful and I’m sitting here waiting.”
Georgie’s husband Kael Hudson, 33, says his wife needs her mother at this time.
“She had a bit of a breakdown on Friday night, when she got the news that her mum couldn’t come down, she had been really holding onto that… having that denied is hard to get your head around.”
Her treatment has been gruelling so far and Mr Hudson is struggling with being in lockdown, working full time and trying to explain to their two children, 2 and 4, what is happening.
“We are in survival mode,” he said. “It’s very difficult, it’s completely new ground for us.”
On Georgie’s second day of treatment, she was taken to the emergency department because she was having heart pains. She then she stayed at hospital until 3 in the morning.