Authorities in the Maldives have arrested three opposition leaders along with nearly 200 others after clashes erupted between police and protesters demanding the resignation of the country's president and the release of a jailed ex-leader.

With the arrests, nearly the entire opposition leadership behind Friday's anti-government protests were detained, opposition lawmaker Eva Abdulla said on Saturday.

Riot police fired tear gas and baton-charged the late night protest on the Indian Ocean islands, said witnesses to what was the biggest show of support for former President Mohamed Nasheed since he was handed a 13-year jail term in March.

Nasheed's Maldivian Democratic Party (MDP) said one of its top leaders were among those arrested on the capital island of Male, while the head of the largest Islamist party in the mainly Sunni Muslim nation was detained.

The streets of Male appeared to be calm on Saturday morning as police put the number of arrests at 193.

While Nasheed's supporters said the "brutal" crackdown could not be justified, authorities insisted they acted lawfully in breaking up the protest.

"The organisers of the protest addressed the protesters and called on all gathered to topple the government and confront the police," a government statement said.

MDP spokeswoman Shauna Aminath said 195 people had been arrested since Friday evening when the protest began.

"All key opposition figures are now under arrest," Aminath told AFP. "It was a brutal crackdown by the regime."

She said the party's chairman Ali Waheed had been arrested along with Sheik Imran, leader of the main Islamic Adhaalath Party, who was an organiser of Friday's protest.

Nasheed's arrest

The protest came only hours after the United Nations criticised the jailing of Nasheed on March 13 on anti-terror charges as "arbitrary" and said the sentencing had followed a "vastly unfair trial".

Yameen came to power in late 2013 after controversially beating Nasheed in a run-off election despite trailing in the first round.

Nasheed, a climate change activist who was imprisoned during the three-decade rule of former leader Maumoon Abdul Gayoom, became the archipelago's first democratically elected leader in 2008.

He was toppled in February 2012 after a mutiny by police and troops that followed weeks of protests over his ordering of the arrest of a top judge who had been appointed by Gayoom.

Despite the backlash, the government has insisted Nasheed received a fair trial and has told its critics to respect the verdict.

"A free and fair trial has happened. A verdict has come," Foreign Minister Dunya Maumoon, who is Gayoom's daughter and Yameen's niece, said last month.

Known for its luxury island resorts, the Maldives became a multiparty democracy in 2008 when Nasheed was elected president, ending the autocratic 30-year rule of Gayoom.

Source: Agencies