The Australian Vaccination Skeptics Network posted a black and white image of a woman with a man forcibly holding his hand over the woman's mouth on its Facebook page on Thursday afternoon.

The poster claims that vaccinations are "forced penetration" and states that people should have a choice over what goes into their own bodies.

It is not the first time the group has made the same comparison. In a tweet in January 2011, the group compared a court ordering a five-year-old girl to be vaccinated to "court orders rape of a child".

Almost immediately, supporters of the group expressed their disgust, with one commentator, Rachelle Taylor, posting: "This is disgusting. Are you saying you believe your child being immunised is as bad as your child being raped? This could also be very triggering for victims of sexual assault."

The group responded to one comment on its page, defending its decision to liken vaccines to sexual assault.

"This post isn't tasteless - it is honest. What truly IS tasteless is our elected government trying to tell us that we have to vaccinate our children even if we don't believe it is best for their health," the group said.

Fairfax Media contacted AVSN for further comment.

Domestic Violence Victoria CEO Fiona McCormack said the comparison was "so irresponsible and inappropriate".

"To compare a doctor injecting a child against something like the measles to rape … it's obscene."

Shadow Minister for Health, Catherine King, told Fairfax Media the group should immediately remove the post and apologise.

"At a time when a Royal Commission is uncovering the true horror of child sex abuse, equating doctors with rapists shows how completely unhinged the AVSN has become," she said.

It is not the first time the AVSN has courted controversy. In the past it has been accused of bullying and intimidating the parents of a baby girl who died from whooping cough.

Former head of the network, Meryl Dorey, was accused to attempting to access the baby's medical records the day before her funeral.

In January, a nation-wide lecture tour from American anti-vaccine doctor Sherri Tenpenny was cancelled after pressure from doctors and medical groups forced most venues to cancel their bookings for the lectures. The AVKN has strongly supported her aborted tour.

The group was forced to change its name from the 'Australian Vaccination Network' over repeated claims the name was misleading.

The New South Wales Fair Trading Department received complaints about its name, with the Australian Medical Association stating it sounded like it could be a government agency.

Despite challenging a direction to change its name, the Administrative Decisions Tribunal forced the group to find a new title.