UN Secretary-General Ban Ki-moon said on Saturday that he was "deeply disappointed" after Myanmar's military ruler rejected his second and final request to meet jailed opposition leader Aung San Suu Kyi.

Ban met with Senior Gen Than Shwe for another inconclusive round of talks that failed to win any immediate concessions or accomplish one of the main goals of his trip - to see Suu Kyi in jail.

"I pressed as hard as I could," Ban told reporters. "I had hoped that he would agree to my request, but it is regrettable that he did not."

Their meeting took place in Naypyitaw, the junta's remote administrative capital, and lasted about 30 minutes. Ban then flew to Yangon and was scheduled to leave Myanmar on Saturday evening.

Ban said the junta chief told him repeatedly that "he really wanted to agree to my request" but because Suu Kyi was on trial he did not want to be seen as interfering with the judicial process - or being pressured by the outside world.

"I am deeply disappointed that they have missed a very important opportunity," Ban said.

Suu Kyi has been detained by the ruling generals for nearly 14 of the past 20 years and is now on trial charged with violating her house arrest. She faces five years in prison if convicted in a trial that has sparked global outrage.

Ban embarked on the two-day trip saying he hoped to win freedom for Suu Kyi but predicted it would be "a very tough mission."

The UN chief talked for two hours on Friday with Than Shwe, who rarely meets with world leaders. He left that meeting saying his initial request to see Suu Kyi was not granted but he was still awaiting a final reply.

It was Ban's second visit to Myanmar since Cyclone Nargis devastated much of the country last year. His first visit managed to persuade the military government to ease access for hundreds of foreign aid workers who had been restricted from entering cyclone-affected areas.

He also oversaw a conference that raised up to $150 million in emergency relief funds. However, the UN has been unable to budge the junta on its refusal to free its estimated 2,100 political prisoners, including Suu Kyi.

Ban was scheduled to fly over the cyclone-devastated zone on Saturday afternoon and then meet with foreign diplomats in Yangon before leaving.

Suu Kyi's widely criticised trial was set to resume after a monthlong delay on Friday, the same day the UN chief arrived. But the court met for a brief session to adjourn until July 10.

In May, Suu Kyi was charged with violating the terms of her house arrest when an uninvited American man swam secretly to her lakeside home and stayed for two days.