During the three-month amnesty running from 1 July, people can hand in unregistered weapons without the fear of prosecution, the government says.

Those caught outside that period face fines of up to A$280,000 ($212,730; £166,480) or up to 14 years in prison.

It is estimated that there are as many as 260,000 illicit guns in Australia.

Justice Minister Michael Keenan said illegal guns were used in recent terror attacks in Australia as well as for organised crime.

"This is an opportunity for people to present the guns to authorities, no questions asked and with no penalty," he said.

"If people don't take that opportunity, the penalties for owning an unregistered or illegal gun in Australia are very severe."

Australia brought in a similar amnesty deal after the 1996 shootings in Port Arthur.

Attacker Martin Bryant killed 35 people in the historic tourist town in Tasmania - the worst mass shooting in Australia's history.

In recent years the authorities have been expressing growing concern over the threat of possible terrorist attacks in the country.

Last month, they said they were treating as a "terrorist incident" a siege in Melbourne in which a gunman was killed.

In 2014, a 16-hour hostage situation in a Sydney cafe ended with three people dead, including the armed hostage-taker.