During the federal election campaign, Scott Morrison put dealing with the activists on par with terrorist foreign fighters.

The prime minister promised people who trespass on farms would be thrown behind bars or fined up to $12,600.

Attorney-General Christian Porter insists the new laws are needed, despite trespass onto private property already being an offence.

"Trespass onto agricultural land has the potential to cause food contamination and breach biosecurity protocols," Mr Porter said while introducing the legislation on Thursday.

"It can also lead to farmers and their families feeling unsafe on their own land."

The legislation includes two new offences, the first invoking up to one year in prison, while more serious aggravated offences could result in five years behind bars.

The lesser offence involves someone inciting others to trespass on agricultural land, while the more serious crime includes instances when activists incite others to damage property and steal livestock.

"This offence and the substantial penalty proposed, reflects the gravity of these more serious forms of conduct and the substantial loss of income that could follow," Mr Porter said.

The bill also includes protections for journalists and whistleblowers, when it's in the public's interest to know of questionable farming practices.

But the protection for journalists won't apply if a news article suggests activists should trespass on farms.

The issue exploded earlier in the year after animal rights group Aussie Farms published details and addresses of producers in an online map.

A series of farm invasions aimed at highlighting cruelty in agriculture prompted the coalition to talk tough against the activist group.

Aussie Farms refused to take the page down, arguing it was promoting transparency in agriculture and fighting animal welfare abuses.

Amid a bitter impasse between farmers and vegan protesters, the Morrison government promised to crack down on "green-collar" criminals.

Australian Associated Press