A Saudi journalist has been sentenced to five years in prison over tweets deemed inciting public opinion against the kingdom’s rulers, Amnesty International said on Friday.

A Saudi journalist has been sentenced to five years in prison over tweets deemed inciting public opinion against the kingdom's rulers, Amnesty International said on Friday.

Alaa Brinji, who has reportedly already served two years behind bars, was found guilty on Thursday of a list of alleged charges including "insulting the rulers (and) inciting public opinion," the rights group said in a statement.

Brinji was also convicted of "accusing security officers of killing protesters" in the town of Awamiya in Saudi's restive Eastern Province, it added.

In addition to the jail term, Brinji has been slapped with a fine of 50,000 riyals ($13,333) and an eight-year travel ban, it said, pointing out that he has been in detention since May 2014, including an initial period of incommunicado solitary confinement.

Amnesty's regional deputy head James Lynch slammed Brinji's sentence as "utterly shameful".

"He is the latest victim of Saudi Arabia's ruthless crackdown on peaceful dissent, where the aim appears to be to completely wipe out any and all voices of criticism," he said.

"Putting someone behind bars for peacefully exercising his legitimate right to freedom of expression, and defending the rights of others to do so, is a complete distortion of the very notion of justice.

"The authorities must ensure his conviction is quashed and release him immediately and unconditionally," Lynch added, insisting that Saudi Arabia "must be held accountable for its gross and systematic violations of human rights."

Amnesty said Brinji worked for Saudi newspapers Al-Bilad, Okaz and Al-Sharq.