Police are treating a blaze which damaged an empty flat in central Queensland as suspicious.

A blaze that engulfed an empty flat in central Queensland is being treated as suspicious.

Emergency crews were called to Gladstone where flames had engulfed the unit late on Saturday night.

A 19-year-old man was hospitalised for smoke inhalation after running into the flat, believing there were people sleeping inside.

Investigations into the cause of the fire are continuing.