Melbourne: Australian Prime Minister Scott Morrison says the commonwealth is prepared to join a legal challenge if any landholder wants to launch legal action against animal rights activists protesting on their farms.

Campaigning in Brisbane on Monday, the prime minister blasted recent protests by activists he dubbed “green collared criminals” and declared “if there are pastoralists, farmers, graziers, that are in a position to bring a civil action against these groups looking to undermine their livelihood, the commonwealth is totally open to supporting them in a test case to show these green criminals [it is not on]”.

The comments follow protests around the country, including a demonstration in Melbourne on Monday morning involving more than 100 activists that brought a busy CBD intersection to a standstill.

Two 17-year-olds, a 15-year-old and 36 adults were charged with offences relating to obstructing a roadway and resisting police.

Other protests in Victoria targeted abattoirs at Corio, Pakenham, Laverton North and Bacchus Marsh in Victoria.

In a series of protests across the country, nine people have been charged after chaining themselves to machinery at an abattoir run by Southern Meats in Goulburn, New South Wales in the early hours of Monday. Police were called to cut the protesters free.

The group consisted of three men, one 46 and two aged 22, and six women, aged between 21 and 61.

Another cohort of animal rights protesters say police tailed them to a Queensland abattoir where they broke in and chained themselves up before negotiating their way out with three sheep.

No one was arrested or charged after 19 activists invaded the Carey Bros Abattoir near Warwick before dawn on Monday.

However, the owner of the business, Greg Carey, indicated on Monday that he wanted the activists charged.

“They are trying to bring our primary agricultural industry to its knees using stand over tactics ... this is un-Australian and harms the livelihood of many,” he told the ABC.

Morrison also urged state governments to take action.

Two people were charged with trespassing after an investigation following a mass protest on a southern Queensland feedlot last month.

The action was linked to a nationwide protest for animal rights which saw a cafe in Victoria close after what the owners said was “nearly four months of constant harassment”.

On Monday morning vegan activists blocked the intersection of Flinders and Swanston streets in the heart of Melbourne for several hours.

The Melbourne protesters chained themselves to vehicles about 7am, preventing trams and cars from getting through, and held up signs saying: “This is a peaceful protest” and “SOS animal emergency climate emergency”.

Vans draped in black and emblazoned with the web address of a vegan documentary parked in the middle of the intersection. Protesters had set up a television screen at the intersection which was playing the footage.

Police covered some protesters in blankets while they used angle grinders to cut the chains, before leading them away into custody. They later confirmed 38 people, including two 17-year-olds and a 15-year-old, were arrested.