The United Nations secretay general Ban Ki-moon has urged Myanmar to move swiftly to accept international aid in the wake of Cyclone Nargis.

The Cyclone has killed around 23,000 people and left more than 42,000 missing, mostly in the Irrawaddy delta.

Speaking at a news conference, the UN chief said the Myanmar authorities must show flexibility to ensure help reaches those who need it most.

"I have been urging the authorities of Myanmar to be flexible in opening their boundaries so that all aid workers can enter into Myanmar. To, first of all, issue visas expeditiously and, if possible, exempt all visa requirements for all UN aid workers so that we can reach out to needy people."

Four UN aeroplanes carrying high-energy biscuits, medicine and other supplies reached Yangon on Thursday.

Meanwhile, more international relief supplies begin to reach Myanmar. Aircraft carrying relief materials from parties including the UN'S World Food Program, European Union and China Indonesia arrived at the Yangon International Airport on Friday morning.