EIGHT anti-war activists have been arrested after they broke into a top-secret military island off the coast of Victoria overnight.

The protesters are members of the Swan Island Peace Convergence, which has been blockading the only entrance to the Swan Island base, off Queenscliff, since Sunday.

A rebel group of demonstrators broke from the blockade this morning and sneaked into the facility, which has become Australia’s finishing school for special forces and counter-terrorism teams.

Victoria Police spokeswoman Leonie Johnson said eight people had been arrested this morning over the break-in.

Ms Johnson said the seven men and one woman would be charged with Commonwealth trespassing offences.

“We will continue to monitor the situation,” she said.

Protester Fiona Taylor said all eight, aged in their 20s to 50s, had since been released.

She said they entered the base to “try and disrupt Australian involvement in the US alliance and its participation in the war in Iraq”.

“We think it is misguided and will fuel ISIS,” she said.

“There are clear alternatives to blocking ISIS — blocking oil supply channels, having arms embargoes and support of a regional solution all will cripple ISIS without breeding another generation of militant extremists.”

Ms Taylor said the Peace Convergence had blockaded the island’s only entrance every year for the past four years in protest against Australia’s involvement in the wars in Afghanistan and Iraq.

She said between 70 and 100 people attended the week-long blockades each year, among them “a lot of children and families”.

samantha.landy@news.com.au