The incident occurred sometime between 11pm Tuesday January 5 and 12pm on January 6.

An unknown number of perpetrators gained access to the showground before forcing their way into the Kempsey Show Society office. No items were stolen in the incident, but damage was caused to the inside of the office and the door.

President of the Kempsey Show Society Stewart Witchard said the door will need to be replaced.

"We're going to have to install a new door with money that could have been used elsewhere," he said.

"And although nothing of value was taken, the mess that was left behind means we've had to spend time organising and cleaning up the office.

"We never keep cash on the premises and this has just been very disheartening for the show society and has been a blow to all of the volunteers."

This incident has occurred in the midst of the show society planning the 2021 event.

"The community has dealt with a lot over the past two years and the show society is working hard to put on a great event for the community in April and this incident is just really disappointing for us and the community," Stewart said.

Kempsey Showground coordinator Lisa Powlesland said installing a new door will cost thousands of dollars that would have been used for upgrades around the showground.

"It's going to cost $3900 to fully replace the damaged door and that money could have been spent on providing portable panelling for the animal section at the showground," she said.

Since Lisa took on the role of coordinator of the showground in June 2018, she has experienced five break and enter incidents.

"There has also been an increased number of incidents of antisocial behaviour in and around the showgrounds and people need to realise this is a community space and we're not going to stand for that kind of behaviour."

Increased security for the showground is also being looked at following the recent break-in.

"We are looking at installing CCTV at the showground so this doesn't happen in the future," Lisa said.

Police are investigating the incident and anyone with information is urged to contact Kempsey Police on 6561 6199.