Extreme vegan activists who invade farms will be targeted with the same urgency as returning foreign fighters under a re-elected coalition government.

Prime Minister Scott Morrison has promised to pass legislation to make trespassing protesters face up to one year in jail if he wins the May 18 election.

The new penalties, to be legislated in the first parliamentary week, would be given the same priority as measures to stop and control foreign fighters returning to Australia.

Vegan activists at Melbourne CBD (AAP)

The announcement comes after a series of farm invasions aimed at highlighting cruelty in the agriculture sector.

"It's disgusting. It's appalling," the prime minister told reporters on a farm in Eumungerie, north of Dubbo in NSW, on Saturday.

"It's just not acceptable that people's properties, their livelihoods, their homes would be targeted as part of a deliberate campaign to bring their livelihood down.

"This is just deplorable."

Vegan activists shut down an intersection in Melbourne. (AAP)

Mr Morrison cited research that showed 40 per cent of school children believed farming damages the environment.

"This is a lie that is being told to our kids and we have to correct it," he said.

The government has been examining ways to crack down on an online map of farmers' addresses and contact details, which it says encourages activists to invade properties.

Scott Morrison shears a sheep at a farm north of Dubbo. (AAP)

The group behind the map, Aussie Farms, is adamant the information is already available publicly and agriculture should be more transparent about animal welfare.

Agriculture Minister David Littleproud described the activists as "un-Australian", warning the disconnect between the city and the bush needed to be fixed.

"If the prime minister and I and 100 of my best mates stormed a house in Sydney with our phones, I'm sure the police would be there with handcuffs to take us to the clink," he said.

"These farming families deserve the same support."

Scott Morrison brings out a sheep to be shorn at a farm north of Dubbo. (AAP)