They said that night demonstrations were staged in at least four areas of the oil-rich Gulf state and that riot police used teargas and stun grenades to disperse the protesters. There were no reports of injury.
The demonstrations were not previously announced and began at the same time in a coordinated way to press demands for abolishing the new parliament and scrapping a disputed amendment to the electoral law.
"It was decided by opposition youth activists to stage night protests from tonight until next Saturday when the opposition plans a major procession," a youth activist told AFP requesting anonymity.
Saturday's snap polls were boycotted by the opposition and all the 50 seats were won by pro-government candidates, including a record 17 seats by the Shiite minority.
The Islamist, nationalist and liberal opposition boycotted the polls in protest against the amendment of the electoral law which the opposition says it enables the government to control the outcome of polls.
Head of the National Election Commission Ahmad al-Ajeel said Monday that voter turnout was 39.7 percent while the opposition claimed it was only 26.7 percent.
Kuwait Emir Sheikh Sabah al-Ahmad Al-Sabah earlier Monday accepted the resignation of the cabinet in a routine step required after the election.
He also invited the new parliament to hold its inaugural session on December 16.
The Gulf state has been rocked by a series of political disputes since mid-2006 between MPs and the government.