Attorney-General Christian Porter on Thursday introduced draft legislation to federal parliament setting out the legal pathway for a national emergency declaration.

It's a key recommendation from the royal commission into natural disaster arrangements, which noted Australia will experience more frequent and intense natural disasters.

The probe was launched after last summer's devastating bushfires where deadly blazes simultaneously raged across the country.

"The experiences of the Black Summer bushfires and COVID-19 have left an indelible impression on Australia," Mr Porter said.

The threshold is an emergency that is or could cause nationally significant harm.

It could occur on land, sea - including offshore areas - and in Australian airspace.

The states can either ask the prime minister to do so, or it can be done if various thresholds around the seriousness of a natural disaster are met.

The bill also creates two new powers, one giving ministers the ability to suspend red tape if it helps the public during an emergency.

The other is for the prime minister to require Commonwealth bodies to report on stockpiles, resources, assets, as well as recommendations to respond to a national emergency.

The legal changes also tweak a range of bills to ensure there are not roadblocks once a national emergency is declared.

For example, it allows aircraft to land at certain airports after curfew if they're being used to help with the emergency.

The changes also give the okay for actions to occur even if they are likely to have a significant impact on the environment, if doing so helps prevent, mitigate or deal with a national emergency.

Australian Associated Press