A cycling group for people with disabilities was cancelled after travellers pitched up at their meeting spot.
About a dozen traveller caravans pulled onto Moor Park in Preston on Sunday.
Preston City Council has said they the group will be evicted if they do not leave of their own accord.
Monday’s Wheels For All cycling group had to be put off after the travellers moved onto the park and now organiser Yunus Suleman says he may well have to cancel the group today and tomorrow too.
“It’s about the safety of the participants and safety of the bikes,” he said.
“I decided to close it on Monday and I’ll probably have to close it on Wednesday and maybe Thursday. We’ll have to see what happens with the council.”
A spokesperson from the city council said: “A group from the travelling community arrived on Moor Park on Sunday, September 9.
“Officers have attended to speak to them and welfare checks will soon be carried out by colleagues at Lancashire County Council.
“Eviction proceedings against the group will be commenced should the families fail to leave the site voluntarily.
“This is a large public park and it’s hoped disruption to local residents, businesses and park users will be minimal.”
Passers by said the travellers, parked near the Blackpool Road side of the park, could be seen hanging out their washing and letting their horses graze.