Key Points:

Three people were evacuated but no one was believed to be injured after a fire at a Hamilton coolstore overnight.

Firefighters were called to the CTK Coolstore in the Hamilton suburb of Frankton at 3.20am.

The coolstore was joined to other buildings and was engulfed by fire.

By 6.30am, the blaze was believed to be under control and several appliances had left the scene, northern fire communications shift manager Megan Ruru told NZPA.

Four appliances remained at the scene and two fire safety officers were investigating the cause, she said.

It was to early to say whether the fire was suspicious.

No one was injured, but three people were evacuated. No one else was believed to be in danger, Ms Ruru said.