Dozens of vegan activists have avoided criminal convictions over a protest which shut down parts of central Melbourne, but have been ordered to pay $100 each to an animal sanctuary.

Key points: Vegan activists have been ordered to pay $100 fine each to animal sanctuary

Vegan activists have been ordered to pay $100 fine each to animal sanctuary The State Opposition criticised the penalty, saying the activists were let off too lightly

The State Opposition criticised the penalty, saying the activists were let off too lightly As part of the court order, the protesters are required back in court on January 13

Thirty-six people admitted causing an obstruction at the intersection of Swanston and Flinders streets on April 8, in a protest against animal husbandry.

Outside the Melbourne Magistrates' Court on Monday, they maintained they weren't the "real criminals".

"We must always question who the real criminals are — those who seek a kind and sustainable planet or those who seek to destroy it whilst causing immeasurable suffering in the process," spokeswoman Kristin Leigh told reporters.

The group — including protesters Kristin Bacon, Kim Dutton and Douglas Leith — took responsibility for obstructing police and drivers in the city.

They avoided a conviction as part of a court order, and must pay $100 each to Edgars Mission Farm Sanctuary in the Macedon Ranges.

The activists blocked cars and trams outside Flinders Street Station. ( ABC News: James Oaten )

Another four activists who previously faced court over the same protest were also handed the same penalty.

"The actions we took are confrontational, but we also need to get some perspective. An inconvenience is nothing compared to the brutality and death so many innocents suffer," Ms Leigh said.

"When you are aware of the horrific abuse, torture and suffering trillions of land and sea animals unnecessarily endure every year and you know your actions have helped to draw attention to that, it is possible to take responsibility but not possible to feel regret."

The State Opposition criticised the penalty, saying the activists were let off too lightly.

"I think the general community would think [the fine] is a slap on the wrist," deputy Liberal leader Georgie Crozier said.

"I certainly do, and I think that those animal activists need to understand that they can't go on and disrupt Melbourne's streets and potentially put people's lives at risk by blocking ambulances and diverting police resources."

As part of their court order, the protesters are required back in court on January 13.

AAP/ABC