KUWAIT CITY (AFP) - The opposition vowed Sunday to press on with protests until a newly elected parliament is abolished and a disputed law scrapped, a day after Kuwait's Shia minority emerged as main victors of a largely-boycotted vote.

"We will continue with our national and peaceful protests under the umbrella of the constitution to bring the downfall of the new parliament," Islamist opposition leader and former MP Faisal al-Muslim told AFP.

"We will use all peaceful and constitutional tools, including demonstrations and gatherings," said Muslim.

Organisers of three huge opposition demonstrations ahead of the election announced on their Twitter account Sunday a plan to organise a new rally but did not fix a date.

The opposition has no representative in the 50-seat parliament after it opted to boycott Saturday's polls to protest the government's unilateral amendment of Kuwait's key electoral law. Under the previous law, a voter was able to choose a maximum of four candidates which was reduced to only one in the new system.

The opposition, which held 36 seats in a dissolved 2012 parliament, has described the move as unconstitutional and says it enables the government to manipulate elections. "We call for scrapping this parliament and the repealing of the one-vote decree because this parliament does not represent the Kuwaiti people," Muslim said.

Kuwait's three biggest bedouin tribes - the Awazem, Mutair and Ajmans with a combined population of over 400,000 - won only one seat against an average of 17 in previous parliaments because of the boycott.

"The majority of the Kuwaiti people sent a direct and transparent message to the emir ... rejecting the new measures adopted by the government and calling for the new assembly to be abolished," Muslim said.

On Sunday, Emir Sheikh Sabah al-Ahmad Al-Sabah, the crown prince and prime minister congratulated the newly-elected lawmakers.

But a majority of the Kuwaiti people heeded opposition calls to boycott the election on Saturday, "which is evident from the fact that voter turnout was less than 27 percent," Muslim argued.

The information ministry website reported early Sunday that turnout was 38.8 percent. It later put the figure at 40.3 percent based on a report by international observers.

Because of the massive boycott, Shia candidates won an unprecedented 17 seats, almost doubling their strength from nine seats in 2009. Seven Shias won seats in the polls last February that the courts nullified.

New Shia MP Khaled al-Shatti said the new parliament would help restore stability. "The new assembly will help bring political stability through achievement. It will push with the stalled development, issue necessary legislation and resolve problems facing people," Shatti told AFP. The new parliament also has three women and as many as 30 newcomers. Sunni Islamists were reduced to just four MPs from 23 in the February parliament.

But the opposition will continue to refuse to "deal with the new parliament or the next government," as long as the controversial law stays and the new assembly is not dissolved, Muslim said. A member of February's scrapped parliament, Faisal al-Yahya, predicted the new parliament would not be able to continue as protests would escalate. "Results of the unconstitutional polls will be a major turning point in Kuwait's political history and will provide the popular movement with new unprecedented momentum," Yahya said on his Twitter.

OPEC member Kuwait has been rocked by a series of political crises which stalled development despite a huge wealth from oil. Saturday's vote was the second in 10 months and the fifth since mid-2006.

The cabinet is expected to resign on Monday to allow the formation of a new government following the polls.