The streets of the Saudi capital Riyadh were unusually quiet on Monday as many expatriates stayed at home to avoid the start of a government crackdown on illegal foreign workers.

Building sites were deserted, Riyadh's stuttering rush-hour traffic flowed smoothly and many shops and market stalls were closed in normally busy neighbourhoods that are home to large numbers of Saudi Arabia's lower-income foreign community.

The government of the world's top oil exporter has promised raids on businesses, markets and residential areas to catch expatriates whose visas are invalid because they are not working for the company that 'sponsored' their entry into the kingdom.

In the Riyadh Industrial Zone, where many workers are foreigners, most shops were closed on Monday morning, according to a witness who said he saw a dozen people scurry for cover when they heard a police siren from a nearby road.

"Nobody has come to buy anything at all today. It's a very bad situation," said Abu Safwat, a Syrian who owns a machine parts shop in the area.

The enforcement of visa rules is another effort to end a black market for cheap imported workers, cut the foreign labour force and free up private-sector jobs for Saudi nationals.

"The field security campaign, in coordination with the Labour Ministry, will take place in all cities, provinces, villages and rural towns," Interior Ministry spokesman Major-General Mansour Turki said in a statement on Sunday.

The official Saudi unemployment rate of 12 percent excludes a large number of citizens who say they are not seeking a job.

Raising private sector employment in a country where most Saudis are in government jobs, and where businesses employ more foreigners than locals, is a major challenge for the kingdom.

About nine million foreigners, mostly unskilled labourers or domestic workers, live alongside 18 million Saudis. The money they send home is vital for their own nations, such as Yemen, Ethiopia, the Philippines, Indonesia, India, Pakistan and Egypt.

LABOUR BLACK MARKET

For decades, Saudi authorities ignored irregularities such as working for firms that had not sponsored their visas or in trades other than those listed on their immigration documents.

That spurred a black market in which foreigners overstayed visas, set up illegal businesses or took low-paid jobs in areas where authorities wanted Saudi workers hired on higher salaries - thwarting implementation of wide-ranging labour reforms that penalise companies for hiring more foreigners than locals.

In March the labour and interior ministries began raiding offices and markets before declaring an amnesty in April to enable foreigners to correct their visas without being fined.

Before the amnesty expired on Monday the government issued repeated warnings for foreigners to correct their status or face punishments including prison, fines and deportation.

Companies employing expatriates without proper visas will also be fined, as will people or firms that charge expatriates a fee to sponsor their visa.

"We want foreigners to remain in the kingdom lawfully," said Deputy Labour Minister Mufrej al-Haqbani in remarks quoted by the local Arab News English-language daily.

A long queue stretched down the road outside one visa office as Arab and South Asian foreign workers tried to leave without paying fines for overstaying. Some carried personal possessions in hopes of leaving immediately.

A Sri Lankan woman working as a freelance maid in Riyadh said she and several of her friends had decided to stay at home in case they were caught up in government raids.

In the Batha district, home to many low-paid foreigners, some shops were shut and only Saudi employees were working in others. Market stalls had vanished from the normally busy street where vendors hawk fruit, vegetables, clothes and mobile phones. – Reuters