The worst drought in decades in Spain is leading to regional disputes over scarce water resources with areas with more reserves resisting transfers to more parched zones.

There has been 40 percent less rain than normal across the country since the meteorological year began on October 1, said Angel Rivera, the spokesman for the National Institute of Meteorology.

"We can say it is the most severe drought in 40 years," he told AFP.

In the traditionally drier Mediterranean regions, a lack of rain over the last 18 months means this is the worst drought since 1912, said the environment ministry's director general for water, Jaime Palop.

The drought has hurt crops and hydroelectric power production as water reserves have dropped to 46.6 percent of capacity, a 20 percentage point drop over the level recorded a decade ago.

The situation is especially critical in the northeastern region of Catalunya whose capital Barcelona is a top tourist draw.

Water reserves in the region of some seven million people are at just 19 percent of their capacity.

If they drop below 15 percent, the water from the dams can not be used as it is too close to the bottom and will have too much sediment.

Without significant rainfall over the coming months, the region will suffer supply problems during the summer and by autumn could face water use restrictions, local officials said.

"The forecast for the next three months is not very optimistic. The precipitation is expected to be normal or slightly below normal," said Rivera.

Alarmed by the situation, the government of the independence-minded region wants to divert water from the river Segre, a tributary of the gigantic Ebro, to Barcelona.

But the government of the neighbouring region of Aragon through which the Ebro flows opposed the plan.

The Catalans accuse the Aragons of wanting to keep its water reserves for controversial projects such a plans to build a "European Las Vegas" with 70 hotels, five theme parks and several golf courses in a desert region.

The central government of Socialist Prime Minister Jose Luis Rodriguez Zapatero, who was re-elected to a second term in a general election last month, rejected the plan as being harmful to the environment.

Under the Spanish constitution, when a river basin is split between regions, it is the central government that acts as the referee in water use disputes.

Shortly after he came to power in 2004, Zapatero reject plans by his conservative predecessor Jose Maria Aznar to divert water from the Ebro to the region of Valencia.

Among the other options which Catalunya is studying to deal with the drought is importing fresh water by boat from the nearby French port city of Marseille or by train from other Spanish regions.

But critics say this option would be too expensive.

The Catalan government is meanwhile building a sea water desalination plant which will produce 60 million cubic metres (230 billion gallons) of drinkable water per year, enough to meet consumption needs for two months.

For farmers, time is ticking away.

"If it rains in the coming days, crops can be saved, if not the situation could become catastrophic," the president of national irrigation federation Fenacore, Andres del Campo, told AFP.

He called for better water management policies because "with climate change, there are going to be more and more torrential rains alternating with periods of drought."

Environmentalists estimate that leaking pipes allow about 20 percent of the water they transport to go to waste.