Beon Energy Solutions compliance and sustainability manager Kirsten Lee said a number of buses with unauthorised visitors had recently attempted to access the site at Lauriston and go for a tour.
"Although we’re glad that there is such interest in the project from the local community, this is an active construction site and only authorised personnel are allowed access, as stated on the signage at the gate," Lee said.
"A construction site of this size comes with a large number of hazards that people not familiar with the site will not be aware of."
Lee said Beon is committed to keeping everyone safe.
It is installing additional signage to ensure the access restrictions are clear.
The solar farm, which is set to start generating electricity by the end of the year, is a joint venture between Genesis Energy and FRV Australia.
Ashburton Mayor Neil Brown was among a group of district councillors who recently visited the solar farm on an information tour organised by Beon.
"The project is an exciting one for our district and a special visit, with health and safety protocols, was organised for councillors," Brown said.
"Members of the public can’t just roll up and take a look.
"This is a construction zone and people need to obey the restricted access signs."