The Kuwaiti government has threatened to revoke the citizenship of people suspected of trying to "undermine the stability" of the oil-rich monarchy, local media reported on Tuesday.
The warning is part of an "iron fist" policy adopted by the cabinet on Monday night, following protests earlier this month over the arrest of a prominent opposition politician.
"The Interior Ministry is assigned to take all measures that are necessary to ensure the presence of the conditions and requirements provided for by Kuwaiti citizenship law number 15 of 1959, both in form and spirit, and especially in relation to the practices aimed at undermining security and stability," the cabinet said in a statement carried by state news agency KUNA.
Kuwaiti political analyst Shamlan Alessa said the measure was aimed at naturalised Kuwaitis who have joined the opposition.
Nasser Al Abdaly, who heads an association to promote democracy, said the move was intended to deter people from expressing any opposition to the government.
Kuwait has suffered bouts of political crisis in recent years amid disputes over election procedures and charges of corruption and mismanagement by former parliament members and opposition politicians against senior government members and loyalists, including members of the ruling family.
The OPEC member, a close US ally with more than six percent of world oil reserves, has been alarmed by the takeover of large areas of Iraq by Islamist insurgents and other forces.
Kuwaiti authorities have been investigating an alleged plot to overthrow the Gulf state's ruling system.
Police last week used smoke bombs to disperse hundreds of people who tried to march from the Grand Mosqueto the main court complex to demand the release of Musallam al-Barrak, an opposition politician who had been detained for questioning for allegedly insulting the judiciary.
The government has also ordered the ministry of social welfare to look into the activities of non-governmental associations to ensure they do not indulge in political activity.
Analysts suggested this measure was aimed at Islamist associations.
"This is directed at the Muslim Brotherhood, as well as some in the opposition who participated in recent demonstrations," said Alessa, political science professor at Kuwait University.
Kuwait's justice and Islamic affairs minister, Nayef Al Ajmi, stepped down in May after a senior US official said he had called for jihad in Syria and promoted the funding of terrorism.
Kuwaiti law does not allow parties to operate in the country. But the government tolerates political societies of various shades in the country of 4 million.
Kuwait allows more political freedom than other Gulf Arab states. It has a lively press and an elected parliament, but has banned public gatherings of more than 20 people without a permit.