LONDON (AlertNet) - Exhausted aid workers are gearing up for the third typhoon to strike the Philippines in less than four weeks, a storm they say could be "disastrous" for people living in the already weakened northern regions.

Within the next 24 hours Typhoon Lupit is due to hit the Luzon area in northern Philippines where thousands of people are already living in temporary accommodation.

"So many people have already been devastated by the two consecutive storms that hit our country," Filomena Portales, Communications director of World Vision in the Philippines, said in a statement.

"Another storm at this point would really be disastrous."

The government has already evacuated thousands of people from the area.

Typhoon Ketsana on Sept. 26 and then Typhoon Parma on Oct.3 smashed into the Philippines triggering massive landslides in rural areas and heavy flooding in the capital Manila. The typhoons killed around 850 and forced hundreds of thousands to flee their homes.

The government has also had to order in extra rice supplies to make up a shortfall because of destroyed paddy fields.

World Vision said that Typhoon Lupit could be more powerful than Parma.

"Our aid workers are already overstretched due to the massive relief efforts that we've been doing in the past three weeks," Portales said.

"If Lupit batters the communities who have yet to recover from the previous wreckage, it would be harder for us to reach those in need."

Other aid groups echoed such warnings.

The American Red Cross said that its staff in the region was exhausted by the relief efforts and that reinforcements were being sent from Manila to help.

"Thousands of people are still living in evacuation centers, mostly schools, or living on the second floor of their homes as the first floor is still under water," said Cristina Hammond, American Red Cross disaster specialist in the Philippines.

"Operations centre staff are discussing how best to prepare and how to send reinforcements to help local staff and volunteers who are exhausted and that might also be affected by the storm."

Medical relief agency Merlin said that disease was spreading among the damaged communities.

"The standing water is creating the perfect conditions for diseases, such as dengue fever, transmitted by mosquitoes," the group said in a statement. "Officials say that there will be a dengue fever outbreak in one to two weeks time."

Dengue fever induces an illness similar to flu and if not treated can kill children and weakened people.

The Philippine's government has also said that leptospirosis -- a bacterial infection caused by exposure to animal urine -- has killed about 130 people and is spreading.

A series of natural disasters in the Asia-Pacific region have stretched aid agencies. Three weeks ago, during the same seven day period that Typhoons Ketsana and Parma struck the Philippines, a tsunami washed over a cluster of Pacific islands and an earthquake hit the Indonesian island of Sumatra.

Merlin said it was trying to stem the spread of disease from the typhoons in the Philippines but that funds for the relief effort were withering.

"At a time when an unprecedented three disasters hit the Asia-Pacific region in a week (including the earthquake in Indonesia and tsunami in Samoa), finding the funding needed is a major challenge," Merlin said.

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