The outages, prompted largely by soaring demand and an ageing, inadequate energy infrastructure, come on top of a sinking economy. The power cuts are also threatening to increase public frustration with a young government already mired in political disputes.

The government has ordered the country to observe new daylight savings time, beginning yesterday, shifting clocks forward an hour. It also said many shops and businesses will be asked to close by 9pm, though it is unclear whether the rule will be enforced.

Government offices are supposed to reduce air-conditioner use, and even billboard lights face restrictions.

The worst of the summer heat has yet to come.

'Our lives have been made miserable,' said Ms Zubaida Bibi, 40, whose pay has shrunk by half, due to electricity cuts at the small thread manufacturer where she works in Multan, a city that routinely experiences 10 hours a day without power.

Any significant relief is at least a year away - and that is if plans for new power plants and other projects work out.

The situation is almost too much to bear for some in a country where summer temperatures soar past 40 deg C.

Officials at the Ministry of Water and Power estimate that Pakistan is between one quarter and a third short of the power it needs.

Last Friday, Prime Minister Yousuf Raza Gilani said the government is committed to resolving the electricity crisis and is aware of people's hardships.

But demand is unlikely to level off in this nation where economic growth has produced an expanding middle class and where high birth rates have pushed the population past 160 million.

The government says it has tried to limit damage to key industries. Many large factories, for instance, are not subject to daytime power cuts, though they must close one day a week.

But the central bank on Saturday said the impact of the power crisis on key industries such as metals, textiles and chemicals was contributing to a slowdown in the national economy.

The new government is pushing ahead with a handful of power projects already in the works while pursuing plans for new power plants.

Some are expected to be ready next year, which could help ease the shortage.

The energy and economic problems are adding pressure to the already unstable ruling coalition.

Political analyst Talat Masood said the government may not be ready to cope if frustrations boil over this summer.

Meanwhile, driving, already a nerve-wrecking experience, has grown more hazardous as traffic lights are switched off to save power.

Dinner parties often take place by candlelight. Restaurants, clothing stores and even some ordinary citizens have purchased generators to maintain electricity.

And students are desperate for the power to stay on - it is examination season.

'We can't study at night and it is like hell to sit in an examination hall for three hours without a fan and water,' said 17-year-old student Amna Haq.

ASSOCIATED PRESS