Millions of Australians are facing dire consequences caused by climate change, a landmark report has revealed.

Rising oceans and flooding caused by climate change will threaten the homes and livelihoods of over a million Australians by 2050, a report warned on Monday.

The National Climate Risk Assessment also warned that fatalities from heat-related illness will soar.

Australia will endure more frequent and extreme climate events, often happening simultaneously, which will put pressure on industry, services and infrastructure, the report found.