Berlin  - Two weeks after Cyclone Nargis, some water-purifying equipment for disaster victims remains snagged in Yangon, according to a German government aid agency on Friday.

There have been protests in the West this week at the insistence by Myanmar's military authorities that only local Myanmar relief workers can work in the cyclone-hit Irrawaddy Delta, where filthy water has been spreading disease as the next band of rain hits.

The THW, Germany's volunteer civil-defence service, said its four mobile 6,000-litre-per-hour water-purifying plants were still at a UN World Food Programme compound in Yangon, three days after the THW's team of 13 Germans arrived.

German diplomats were still in discussions about where they could be employed, said THW spokesman Ewald Nagel in Frankfurt.

"The guys are still cheerful. They want to help people. But it is annoying that they cannot help yet," he said.

Nagel said earlier this week the charcoal-filter plants could only be operated by German experts trained to maintain their chemical equilibrium and constantly test the output in a mobile laboratory. The THW is funded by the German Interior Ministry.

Six smaller and simpler plants sent by the German Red Cross were set to arrive Friday in Yangon on a cargo plane.

Those plants, each with a capacity of about 1,560 litres per hour, were a gift and could be operated by Myanmar staff after two to seven days of training, said Red Cross spokeswoman Svenja Koch in Berlin.

Six trucks will next have to move the plants on rain-soaked roads to their chosen sites. The Myanmar Red Cross, which has 27,000 volunteer members, will be able to supply clean water to 15,000 cyclone victims with the six donated plants, Koch said.

German political figures slammed the Myanmar authorities Friday for prohibiting foreign relief workers going beyond Yangon's city limits.

Ruprecht Polenz, chairman of the German parliament's foreign affairs committee, said, "Every day counts now."

Polenz, who belongs to Chancellor Angela Merkel's Christian Democratic Union (CDU), said he was "disappointed" the UN Security Council was not debating the crisis and demanded that UN Secetary General Ban Ki Moon act. Diplomats say China has blocked any debate.

Cyclone Nargis brought a surge of seawater inland in Myanmar's central coast on May 2-3, ravaging the fertile delta and killing 43,318 people, according to the Myanmar government's latest toll Friday. (dpa)