More travellers have arrived at a Holme Valley recreation ground.
About 12 caravans have now moved onto the council-owned site off Springwood Road close to Holmfirth High School.
But a group of travellers who were occupying part of Leeds Road Retail Park in Huddersfield have moved on.
Students at the school have been told not to cross the recreation ground and staff have supervised students arriving and leaving.
Acting headteacher Gail Howe said: “Our students use it as a short cut and we have advised them not to use it because of the number of vehicles on there moving around. We have advised them that there are travellers on the site and to keep a respectful distance.”
She said there had been no effect on the school day as the recreation ground was not used for games lessons.
Kirklees Council has begun legal proceedings to evict the travellers, who moved onto the council-owned site on Wednesday afternoon – but eviction notices take 10 days to come into effect.
Police have powers to move travellers on, but West Yorkshire Police has rarely used them.
The law allows police to remove travellers if there are: two or more of them and a police officer believes they intend to “reside” there; they have been asked to leave by the owner; they have caused damage to land or property; they have been threatening or abusive to the landowner; and they have six or more vehicles between them.
If they fail to leave, or return within a three-month period – they will be committing an offence which carries a maximum three-month jail term.
