The fire started at around 2am and crews remained at the Holyhead Road site into the afternoon.
It is the latest in a string of fires at the wood panel factory, which last week had a decision on its expansion plans deferred amid calls for independent regulation.
No one was injured in the fire and the company said it was "under control".
A spokeswoman said: "A fire was detected in a long log wall at around 2am on the Logyard at Kronospan Chirk and North Wales Fire & Rescue Service were called to deal with the issue.
"The Fire Service currently have three appliances in attendance, the situation is under control, and they are in the process of disassembling the log wall and dealing with the incident.
"The incident occurred in an isolated part of the site and no-one has been injured.
"Kronospan apologises for any inconvenience caused to residents as the incident is dealt with."
Chirk councillor Gareth Baines said: "There has been acrid smoke all across Chirk all morning.
"There have been people contacting me from as far away as Acrefair and Cefn Mawr so it is not just a problem that's contained within Chirk.
"There will be time to investigate the issue but given the amount of smoke I don't think the council or Kronospan can delay independent monitoring any further."
Clwyd South MP Simon Baynes said: "I have been in contact with Kronospan last week about organising a meeting and I will raise this and other environmental and safety concerns expressed by local residents at that meeting."