Prostate Cancer Foundation of Australia chief executive Jeff Dunn said charities were being hit hard by the impacts of COVID-19 and warned many would fold without government support.

"The world is facing a situation unlike anything we have seen in our lifetime," Professor Dunn said.

"Beyond the sudden and tragic loss of life, the economic and social impacts will have far-reaching implications for all of us, imposing additional hardship on the significant number of families in our community who are also facing cancer, chronic disease, illness, and disadvantage.

"They need us now more than ever. We stand ready to support them - but we cannot do that without a lifeline from Government."

Professor Dunn said many charities' resources were stretched following on from bushfires and flooding that affected communities earlier this year.

"The charitable sector exists to serve the most vulnerable in the community. Already there was great pressure on the sector."

He said at the same time, revenue generation was being affected by the virus.

"Charities that rely on community events to raise funds have had their events cancelled for all the right reasons, under the circumstances.

"It's a double whammy. There are revenue challenges at the same time demand is up."

He said those with pre-existing conditions are already more vulnerable to viral illnesses such as COVID-19.

"Many men affected by prostate cancer have weakened immune systems and are less able to cope with a disease as aggressive as this.

"Their families will be at a higher than average risk distress and possible hardship, with treatment plans changing daily and exacerbating patient anxiety."