A Bahraini special court began on Sunday the trial of two former Shiite MPs accused of calling for regime change and spreading rumours linked to pro-democracy protests crushed in mid-March.

Matar Matar and Jawad Fayrouz, who were arrested at gunpoint in early May, appeared in court in two separate cases but facing the same charges, according to state news agency BNA.

They were both accused of "public incitement for regime change and deliberately spreading biased rumours, in addition to taking part in public gatherings," BNA said, adding that they pleaded not guilty.

The military prosecutor argued that their alleged confessions and "technical evidence" were enough to convict them.

The hearing in the case of Fayruz was adjourned until 19 June, while Matar's trial will reconvene on 21 June.

Meanwhile, the court sentenced female poet Ayat al-Qarmazi to one year in prison on charges of "take part in assembly for the purpose of committing crimes, and instigating hatred to the regime," BNA said.

Qarmazi, 20, became known for reading an anti-regime poem at the sit-in protest at Pearl Square, the focal point of protests which was demolished immediately after the demonstrators were driven out.

"By locking up a female poet merely for expressing her views in public, Bahrain's authorities are demonstrating how free speech and assembly are brutally denied to ordinary Bahrainis," said Malcolm Smart, Amnesty International's Middle East and North Africa director said in a statement.

Amnesty said Qarmazi was held incommunicado for the first 15 days of her detention in March, and since then has only been permitted to see her family twice.

She also alleged that she was beaten in detention and tortured with electric shocks, the London-based rights group said.

The court also sentenced Ali Yusof Yaaqub to seven years in prison after convicting him of trying to murder a policeman, while a group of six were given between six months and six years over attempted murder of "civilians," BNA said.

Amnesty said that at least 500 people were been detained in the crackdown, while four have died in custody in suspicious circumstances. Some 2,000 people have also been dismissed or suspended from their jobs.

Bahrain has come under strong criticism from international rights groups since its security forces quashed the month of Shiite-led street protests and carried out waves of arrests in Shiite villages.

Thousands of Shiites rallied on Saturday outside Manama in the first mass rally since the crackdown. The interior ministry said it authorised the demonstration, organised by Al-Wefaq, the largest Shiite formation.