Thailand's influential army chief has warned that the military will strongly fight any moves that threaten the country's system of a constitutional monarchy with the king as head of state.

At a news conference on Tuesday, Gen. Apirat Kongsompong appeared to be targeting intellectuals supporting the Future Forward Party, which according to preliminary figures ran a strong third in the March 24 general election.

Party co-founder Piyabutr Saenkanokkul used to be part of the Nitirat Group, legal scholars who had sought reforms in Thailand's lese majeste law, which carries stiff prison terms for people found guilty of defaming the monarchy.

There has been a strong online campaign since the election to discredit the Future Forward Party and its chief, Thananthorn Juangroongruangkit, with unsupported allegations that it opposes the monarchy.