The party of the front-runner in elections due this weekend in the Maldives called Tuesday for nationwide protests after the Supreme Court suspended the vote, as the Commonwealth expressed deep concern.

Poll favourite and former president Mohamed Nasheed, who was the first democratically elected leader in the holiday islands, slammed the injunction suspending Saturday's run-off vote as undemocratic and the work of a "kangaroo court".

More damning was a strongly worded statement from the Commonwealth group of countries, which has been monitoring the polls. It said talk of annulling the election was "deeply worrying".

"The people of Maldives worked hard to get a democratic constitution, they want it respected and it is their right that the elections deliver a result that reflects the wishes of the majority," said a statement from Commonwealth envoy Don McKinnon.

The Supreme Court on Monday night suspended the run-off while it examines a complaint about the first round of voting by the third-placed defeated candidate, business tycoon Gasim Ibrahim.

Ibrahim's party has called for the results to be annulled because of alleged fraud in the electoral rolls.

"No election anywhere is going to be absolutely perfect and there was no evidence or claim before the election that the voter register was manifestly so deficient as to distort the outcome," McKinnon's statement added.

The Commonwealth, a grouping of former British territories and countries, sent the largest contingent of foreign observers for the first round. They reported the voting as fair and credible.

Nasheed won the first round on September 7 with 45.45 percent and faced a run-off contest against Abdullah Yameen, the half-brother of the islands' former autocratic ruler Maumoon Abdul Gayoom.

"I have been fortunate enough to get the support of 45 percent of the people in the first round of the presidential elections," 46-year-old Nasheed told AFP in an email.

"The dictatorship cannot digest this and have used their cronies through their kangaroo courts to delay their ultimate defeat," he added.

Yameen said there was "nothing unconstitutional" in the Supreme Court's order.

The polls were seen as a test for the Maldives' young democracy a year and a half after the violent ousting of Nasheed, who resigned in February last year following a mutiny by police.

He denounced the process as a "coup", saying his resignation was tendered under duress in a process orchestrated by Gayoom. His deputy, Mohamed Waheed, was installed as president immediately afterwards.

Gayoom denied involvement.

In another development, the Supreme Court Tuesday barred the lead lawyer of the Elections Commission, Husnu al Suood, on a charge of contempt of court along with two other lawyers acting for Nasheed's Maldivian Democratic Party (MDP).

"I have been barred from the court for this case pending an inquiry into my tweets last night regarding the decision to suspend the election," Suood told AFP.

He had tweeted about the constitution being "up in flames".

Nasheed's MDP spokesman Hamed Abdul Ghafoor told AFP the court decision had led to "immense instability and has the potential to trigger violence" as the party called for supporters to take to the streets.

Small protests took place on Monday night after the Supreme Court decision, leading police to use pepper spray to disperse the crowds. One MDP parliamentarian was briefly detained, police said.

"We call upon people not to damage public or private property," said police spokesman Hassan Haneef.

Last year's violent power change hurt the local tourist industry and left a bitter legacy of distrust.

Nasheed, a former pro-democracy campaigner, has railed against the country's judiciary before, which he sees as biased and intent on protecting the interests of Gayoom and a handful of tycoons who control the tourism industry.