Victoria Police say Manus Island refugee protest risked the lives of Melbourne Cup racegoers when activists drove a car onto a train line, deflated its tyres and bolted a woman to the steering wheel.

The Ford Laser was driven across tracks at Ascot Vale on Tuesday, causing train delays ahead of the main race, before being removed as the woman was arrested, police said.

“They left the vehicle in situ with the tyres down and a female protester was bolted to the steering wheel,” Superintendent Tim Hansen told reporters at Flemington.

When police arrived at the scene about 20 protesters scampered, leaving the woman in the car to be extracted by firefighters.

The 27-year-old Moonee Ponds woman is likely to be charged with conduct endangering life, careless driving and unlicensed driving, Supt Hansen said.

Passengers were warned by Metro Trains to expect delays of more than an hour as the Melbourne Cup’s 3pm jump time loomed.

Protestors hung a sign on a crane at Flemington. Photo: ABC

“We are really appalled at the situation on Manus Island and we think it’s really inappropriate for people to be celebrating when there are individuals with no water and no security,” protester Sonia Arquette told AAP on Tuesday.

The car was spray painted with messages including: “evacuate Manus” and “animal liberation – human liberation”.

The group is not aligned with any organisation.

“We don’t want to be doing this but we feel we have no choice when there are 600 people starving,” Ms Arquette said.

In a separate event, two woman climbed a crane at the racecourse and unfurled a banner which read “SOS: Evacuate Manus Now”.

“We are joining with others across Australia to demand that the government evacuate the men on Manus immediately and bring them to safety for processing,” Whistleblowers, Activists and Citizens Alliance spokeswoman Charlotte Lynch said.

Hannah Patchett, 24, and Katherine Woskett, 27, scaled the crane, which is on site as part of a grandstand redevelopment, at about 11.30am.

Police contacted the protest group and negotiated with them and the women agreed to climb down, but not until after the main race.

“This was a really safe result for everyone involved and we were confident the whole way through that the qualifications and experience of those two people who climbed the crane didn’t require immediate police attention,” Supt Hansen said.

Ms Patchett and Ms Woskett have previously scaled the Melbourne Arts Centre in a similar protest and say they will continue to climb buildings and bridges until Australia treats offshore asylum seekers humanely.

Police also arrested a woman for assaulting an anti-racing protester outside the ground and are searching for two other women linked to the assault.

-AAP