All nine Shiite lawmakers stayed away from the national assembly, which held a secret debate on the impact of regional conflicts on Kuwait, following attacks on Sunni-ruled ally Saudi Arabia's diplomatic missions in Iran.
One of them, Saleh Ashour, said: "The anger of Kuwaiti Shiites has reached its peak in recent days with followers of a complete sect" being accused of acting as "agents for Iran and being members of (Lebanese Shiite militia) Hezbollah."
At the same time, authorities are failing to take action against people taking part in fighting in Iraq and Syria, Ashour said on Twitter, a reference to members of Sunni jihadist groups.
Abdulhameed Dashti, another Shiite legislator, wrote on Twitter that he was boycotting the 50-seat parliament for the day, although like the others he did not give an explicit reason.
It comes after a lower court on Tuesday sentenced 22 people, all but one of them Kuwaiti Shiites, who were charged with spying for Iran and plotting attacks in the Gulf country.
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Two defendants, including an Iranian tried in absentia, were sentenced to death while 19 were handed jail terms ranging from five years to life.
Another was fined 5,000 dinars ($16,500) while three were acquitted.
The court said the cell members had links with Hezbollah and the Iranian Revolutionary Guards.
Shiites form around 30 percent of Kuwait's native population of 1.3 million.
The oil-rich emirate has witnessed a rise in sectarian tensions due to regional strife.
Kuwait recalled its ambassador from Iran to protest the attacks on the Saudi missions, and summoned Tehran's ambassador to express its disapproval.
The attacks, carried out by protesters angry at Saudi Arabia's execution of prominent Shiite cleric Nimr al-Nimr, prompted Riyadh to cut diplomatic ties with Tehran.oh/lyn/dr