More than half a doze cars and caravans have formed a camp near the football pitches at King George V playing field, with Portsmouth City Council taking action to move on those present.
It comes as police used Section 61 powers to clear another illegal encampment of 22 cars and caravans in Wicor Recreation Ground on Tuesday evening.
At the Portsmouth site, community wardens from the council have conducted welfare checks and officers are now undertaking legal proceedings, according to Councillor Jason Fazackarley, the council's cabinet member for safety in the community.
He said: ‘We are aware of an unauthorised encampment at King George V playing field. Our community wardens have completed welfare checks and served notice on Monday evening asking them to leave immediately. As they have not left the site we are now undertaking legal proceedings and awaiting a court date and time for a hearing.
‘Please report any crimes or issues with anti-social behaviour to the police for their ongoing assessment.’
Under Section 61 of the Criminal Justice and Public Order Act 1994, police have the power to direct individuals to leave the land and remove any vehicles or property they have with them, according to a spokesman from Hampshire Constabulary.
He said: ‘Failure to comply is a criminal offence.
‘Following a review of the circumstances surrounding the encampment at Wicor Recreation Ground, and in consultation with Fareham Borough Council, police have today utilised these powers, and the group have now left the site.’
Commenting on social media, Fareham Borough Council leader praised council and police officers for their swift work to resolve the issue.
Cllr Woodward said: ‘Events including the AFC Portchester football tournament will be able to go ahead at Wicor this weekend.
‘Special thanks to Donna Jones - (Police and Crime Commissioner for Hampshire and the Isle of Wight) – who helped bring about this very satisfactory result - a real team effort.’
It comes less than a month after an illegal encampment sprung up on Southsea Common for the second time this summer with councillors calling for more powers to remove them.