BANGKOK -- The United Nations warned Friday that the cyclone death toll will rise dramatically unless Myanmar's military rulers let foreign disaster workers in to help cope with the tragedy's aftermath.

The regional spokesman for the world body's emergency relief arm, Richard Horsey, said it was essential for the regime -- which said earlier it was "not ready" for outside relief workers -- to let them in.

"If we don't get this relief effort up to full scale quickly, there's significant risk of a second round of this disaster which could potentially kill as many people as the initial cyclone," he told Agence France-Presse.

"We need a major escalation of the relief effort, not just visas for a few key staff. That means boats, helicopters," Horsey said. "That's what they have to open up to."

One week after the devastating storm killed tens of thousands, the regime -- deeply suspicious of the outside world -- said the country needed outside aid for those still alive, but would deliver it themselves.

"Currently Myanmar has prioritized receiving emergency relief provisions and is making strenuous efforts to transport those provisions without delay by its own labors to the affected areas," it said.

"As such, Myanmar is not ready to receive search and rescue teams as well as media teams from foreign countries."

The United Nations estimates more than one million people have been left homeless by the disaster and, as each hour passes without clean water and food, they are at ever greater risk of starvation and disease.

The regime's official death toll is nearly 23,000, with almost twice as many missing. But a local official in the hard-hit south said the dead in one area alone likely numbered around 80,000.