Tonga's leading pro-democracy MP, Akilisi Pohiva, has been convicted on charges relating to a protest march on June 1 last year.
Along with local businessman Tuí Uata at the Magistrate Court, Mr Pohiva was found guilty of encouraging and abetting with others to obstruct police lawful duties.
The Tongatapu number one people's representative to parliament was ordered to pay a 220 US dollar fine.
On a second charge of encouraging others to commit a crime he was convicted and discharged without a fine.
Our correspondent Mateni Tapueluelu says the charge relates to a protest by public servants who were marching to deliver a
petition to the royal palace.
"The people were staging a protest march and they were ordered by the police not to commence their march before 2pm that day, but Akilisi and the promotoers pushed forward that they should stage their march since there was no threat to peace and security. And because they disobeyed the police order, they were found guilty in the magistrates court."
Mateni Tapueluelu says the case is unrelated to court proceedings stemming from the Nukualofa riot last November, in which Mr Pohiva has been charged sedition.