Seven protesters charged with trespass following alleged break-in at Benalla abattoir

Police are onsite at an abattoir in Benalla removing protesters. (ABC Rural: Annie Brown)

Seven animal activists have been charged with trespassing after they allegedly broke into an abattoir in north-east Victoria and chained themselves to machinery.

Three men and four women were arrested at the scene after allegedly breaking into the Benalla facility in the early hours of Thursday morning. 

It's understood  dozens of activists allegedly broke into and chained themselves to machinery at the pig processing facility.

Some protesters gained access to the roof of the abattoir while others stood with placards near the entrance to the facility. 

Police confirmed seven protesters between the ages of 23 and 53 from Melbourne, Tasmania and New South Wales were charged with trespass offences and bailed to attend the Benalla Magistrates Court at later dates.

"No one was injured during the incident," a police spokesperson said. 

The activists, from the Farm Transparency Project, claim they forced operations at the abattoir to a halt by chaining themselves to a gas chamber used to paralyse pigs before processing, a legal and common industry practice. 

Protesters on the roof of the pig processing facility. (ABC Rural: Annie Brown)

It comes after an expose on ABC TV's 7.30 current affairs program showed illegally obtained footage of pigs being stunned before slaughter across Australia.

Chris Delforce, executive director of the Farm Transparency Project, said dozens of protesters entered the facility around midnight, and that police arrived around four hours later when workers began their shift.  

Mr Delforce believes most Australians are unaware of how commercial pigs are killed for human consumption. (ABC Rural: Annie Brown)

"We chained ourselves onto equipment, some of us, including myself, inside the gas chamber, which is used to stun pigs prior to slaughter," Mr Delforce said.

"A number of us were in the race, the passageway that leads pigs up into the chamber, others were in the holding pens, and some were on the roof with large banners."

Protesters say they want to see changes to the way pigs are killed in Australia (ABG Goulburn Murray: Annie Brown)

The activists are continuing to call for slaughter methods to be changed.

"Everyone who was inside was cut out of the chains and taken outside," Mr Delforce said. 

Authorities were called to the abattoir in the early hours of Thursday morning. (ABC Rural: Annie Brown)

"The team on the roof has just come down but until now we've been able to stop the killing for the day.

"We are here to physically put a stop to the use of this chamber."

Biosecurity signs at the abattoir. (ABC Rural: Annie Brown)