KUWAIT CITY: Kuwaiti security authorities have broken up three cells of the militant Islamic State (IS) group plotting "terror" attacks in the oil-rich Gulf state, the interior ministry said Monday.

Five Kuwaiti nationals were arrested, including a policeman and a woman, who all confessed to plotting attacks against a Shia mosque and an interior ministry target, the ministry said in a statement.

All members of the three cells also confessed to being members of the (IS) group.

Kuwaiti police are still looking for a Gulf man and an Asian who assisted one of the cells, the ministry said.

The action against the cells comes a year after an IS-linked Saudi suicide bomber blew himself up in a Shia mosque, killing 26 worshippers in the worst attack in Kuwait.

A court sentenced one man to death and jailed eight others for assisting the Saudi bomber.

Among those arrested in the latest police action was 18-year old Talal Raja who confessed to have been plotting a suicide attack against a Shia mosque and an interior ministry installation by the end of the Muslim fasting month of Ramazan on Tuesday, the ministry said.

The second cell consisted of a mother and son who were arrested in Syria in the IS-controlled Raqqa and brought back to Kuwait, the ministry said. It provided no details of how they were arrested.

The 28-year old son had cut short his petroleum engineering study in Britain to join the IS after his younger brother was killed while fighting for the group in Iraq, the ministry said.

The third cell comprised of two Kuwaitis, one of them a policeman, who were seized along with two Kalashnikov rifles and ammunition.

The pair confessed to plotting attacks in the country, the ministry said.

In November last year, Kuwaiti police busted an international cell led by a Lebanese man who was sending air defence systems and funds to IS.

Several suspected IS members and sympathisers were tried in the Gulf emirate for a suicide bombing last month claimed by the group.