A massive 5.2-metre saltwater crocodile has been found shot dead in central Queensland, which locals describe as the largest-ever carcass pulled from the river in the area.

The male reptile was found in the Fitzroy River at Etna Creek, about 20 kilometres north of Rockhampton, just after 1pm on Thursday with the bullet still in its head. People for the Ethical Treatment of Animals (PETA) Australia has offered up to $5000 as a reward for information leading to the identification and conviction of the person or people responsible.

Police are investigating after a 5.2-metre crocodile was found shot dead near Rockhampton on Thursday. Credit:Department of Environment and Heritage Protection

State environmental officers were alerted to the dead animal following a tip-off from a member of the public.

The crocodile was taken to a nearby boat ramp, where forensic police examined the carcass before it was taken to a nearby farm for a necropsy.