Thai police officers accidentally stumbled on a sprawling marijuana farm while they were searching for unregistered land.

The officers were first ordered to check several acres of land that allegedly had no deeds in Sa Kaeo, eastern Thailand on Thursday afternoon (May 21).

When they arrived, they were stunned to discover that the 3.2 acres of land were covered with illegal marijuana plants.

Farmer Suppachai Boonprom, 46, who was believed to have been the owner of the land was arrested. More than 1,200 marijuana plants weighing 1,157 lbs was also confiscated from the property.

The man has reportedly pleaded guilty and claimed that he planted them for medical purposes but without official permission.

He was taken to the station and he will be remanded for custody during further investigation.

Police Jung Wongchan said: "Initially, he will be charged for producing drug without legal permission and there might be further charges to be decided after further investigations.''