The Kuwaiti premier is highly tipped to defeat a serious challenge to his rule in a crucial vote Wednesday as the opposition in this oil-rich Gulf state vowed to continue its campaign.

Parliament in OPEC's fifth largest producer is due to vote on a non-cooperation motion filed by opposition MPs against Prime Minister Sheikh Nasser Mohammad Al-Ahmad Al-Sabah, a senior member of the Al-Sabah ruling family.

Opposition MPs, comprising Islamists, liberals, nationalists and tribals, have accused Sheikh Nasser of ordering a police crackdown on an opposition gathering last month and attempting to stifle public freedoms.

The motion needs the support of 25 MPs in the 50-member parliament but a number of opposition MPs said they have secured the backing of around 22 lawmakers, still the biggest challenge ever to a Kuwaiti premier.

The opposition anticipated the vote by organising a massive rally late Tuesday night at which prominent MPs vowed to continue working to bring the downfall of the Kuwaiti government.

"We will not remain silent and we will not accept Sheikh Nasser and his government ... There is not enough space for us and the government to coexist under parliament's roof," cried MP Mussallam al-Barrak.

Addressing the large gathering in Kuwait City, Islamist MP Faisal al-Muslim insisted that Wednesday's vote "is just the beginning" in a prolonged campaign to oust the government.

Security was beefed up around the parliament complex in Kuwait City, with hundreds of policemen controlling the main roads leading to the building.

Kuwait, which sits on 10 percent of proven oil reserves and has assets estimated at 300 billion dollars, has been rocked with almost non-stop political conflicts since Sheikh Nasser was appointed in February 2006.

During this period, parliament was dissolved three times and fresh elections were held and Sheikh Nasser, 70, resigned five times, stalling development projects in the process.

Kuwaiti newspapers and writers warned Wednesday that the current crisis was the most serious in Kuwait's modern history.