UNITED NATIONS — Secretary-General Ban, walking a political tightrope as he seeks to take control of international aid delivery to Burma without offending its ruling junta, is planning a visit to the cyclone-ravaged country this week.

In tough negotiations over the weekend, Mr. Ban came close to cancelling his participation in a planned donor conference for Burma after representatives of the junta demanded that the international gathering in Rangoon take place Saturday. An aide to Mr. Ban who spoke on the condition of anonymity said the secretary-general wanted to avoid giving the impression that he was backing a second round of voting on a constitutional referendum, planned for the same day.

The referendum on the military-backed constitution has been criticized as a political sham aimed at cementing the junta’s hold on power.

The first round of voting was conducted May 9, a week after Cyclone Nargis devastated the country, killing more than 100,000 people and leaving an estimated 2 million without shelter. Critics say the junta is permitting this weekend’s regional conference for political rather than humanitarian reasons.

At the conference, now planned for Sunday, the 10-member Association of Southeast Asian Nations and the United Nations plan to raise funds and coordinate international efforts to assist the victims of the cyclone. The junta has blocked the entry of much of the pledged international assistance, and even as evidence emerges that the military leadership has siphoned off humanitarian goods, it is demanding sole control over the distribution of aid.

The junta yesterday allowed the top U.N. humanitarian coordinator, John Holmes, to conduct a cursory visit in hard-hit areas. The junta’s military commander, General Than Shwe, also made a rare television appearance to announce three days of mourning for the cyclone victims, as China began its own mourning period for victims of the Sichuan earthquake.

Mr. Ban is scheduled to land tomorrow in Bangkok, Thailand, and arrive in Rangoon on Thursday. He will leave Burma on Friday and return Sunday. To date, Mr. Ban’s attempts to contact General Shwe by telephone or mail have been rebuffed, and it is unclear whether the general will meet Mr. Ban during his visit.

Mr. Ban has no plans to meet Burma’s jailed opposition leader, Aung San Suu Kyi, as his mission is “strictly of a humanitarian nature,” spokeswoman Michele Montas said.

“If he is there, he should not play politics on the side of the junta,” the executive director of the U.S. Campaign for Burma, Aung Din, said.

The Washington-based pro-democracy group has documented several cases in which junta members and their allies, many of whom America and other Western countries have placed under strict financial sanctions, have used foreign aid meant for cyclone victims.

“Many countries are contributing a lot of money, but who is going to distribute it?” Mr. Din said. The outside world so far has been “playing the game according to the rules of the junta,” he added.

Control over distribution will be one of the top items on the agenda at Sunday’s donor conference, Ms. Montas said.