UPDATE: POLICE have removed three animal rights activists from a live sheep export ship in Fremantle this afternoon.

Police remain at the Fremantle Port this afternoon after protesters entered the docks about 4.20am and locked themselves to the front gate and railings of a ship.

A WA Police spokeswoman told Weekly Times Now six people had been charged and three people had been recently removed from the Al Shuwaikh.

Four men aged 31, 19, 26 and 22 have been charged with trespass.

The spokeswoman said another three people who had been on the ship were expected to be charged with trespass offences.

She said the protesters used home-crafted thumb locks and police needed to use specialised equipment to cut them free.

Police spokesman Bill Munnee said about 25 police including officers from the Tactical Response Group, Fremantle Traffic and general duties officers were at the scene to keep an eye on about 30 protesters.

"We respect the right of all people to protest, but they must do so lawfully and peacefully," he said.

"Police are not here to take sides. We're here to make sure that nobody gets hurt."

Protester Michael Montgomery said he believed the live export trade was cruel to the sheep.

"It's quite inhumane, the condition that they're kept in," he said.

"A great number of them die and they're in such cramped conditions that they are walking on and eating around their dead comrades.

"It's something that can be replaced with abattoirs here, with chilled meat export, which can be far more humane."

Mr Montgomery said the protesters would continue to take action in the future to highlight the plight of the animals.

"I'm concerned for the animals, the same sheep that kids pet and cuddle with their furry coat and sing songs about," he said.

"Non-violent direct action has been proven to work in many social movements."

Fremantle Ports external affairs manager Ainslie de Vos said the boat was bound for the Middle East.

"The ship is continuing to load and has been all morning with little disruption," Ms de Vos said.

WAFarmers meat section president Jeff Murray said protesters were deliberately attempting to disrupt a ship that was sailing under the new Exporter Supply Chain Assurance System.

"The actions were a clear attempt to disrupt a legitimate trade which is operating under Federal Government approval and rigorous standards of animal welfare," Mr Murray said.

"Clearly this is a case of extremism by only a handful of activists and does not represent the views of the broader community," he said.

Animals Australia spokeswoman Lisa Chalk told Weekly Times Now the protesters were not connected to Animals Australia.