A Thai construction tycoon has been sentenced to an additional one year in prison for bribing a park ranger in relation to a high-profile case of poaching endangered animals in a wildlife sanctuary last year.

A Bangkok court said in a statement that it sentenced Premchai Karnasuta, the president of Italian-Thai Development PLC, on Tuesday for attempting to bribe the sanctuary's chief ranger, who had arrested him, to let him go free.

In February last year, Premchai and his company's employees were found with guns and the carcasses of a black panther and other animals in the sanctuary where they had set up a camp to hunt animals.

Premchai was convicted on some of the charges in March and sentenced to 16 months in prison.