UN chief Ban Ki-moon arrived on Thursday in Myanmar to press the junta to accept a full-scale relief operation for cyclone survivors, according to an AFP reporter at the airport.
Ban, the first UN chief to visit Myanmar since 1964, is due to meet with senior government officials on Thursday morning and then tour the Irrawaddy Delta, which suffered the brunt of the cyclone.
The disaster left more than 133,000 people dead or missing in early May.
On Friday, he is scheduled to fly to the junta's remote capital Naypyidaw where he will meet with the regime's reclusive leader Than Shwe, a Myanmar government official said.
The last trip by a UN secretary general was in 1964 by U Thant, a Myanmar national who led the world body when this country was still known as Burma.
Armed police lined the roads leading from the airport, while soldiers busied themselves cleaning the storm-damaged streets of Yangon for the UN head.