U.N. Secretary-General Ban Ki-moon has promised Haitians he is focused on maintaining donor solidarity as the quake-torn nation struggles to rebuild, the organization said.

The effort will include an international donors' conference at the United Nations headquarters in New York on March 31, Ban said, according to a Sunday news release.

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Providing shelter to displaced people, sanitation and reconstruction remain top priorities, Ban said during his second visit to the country since a massive earthquake struck January 12.

"We have provided at least 700,000 people with tents, tarpaulins and plastic sheeting," he said. "This however is not enough, as it covers just 60 percent of the 1.3 million displaced persons."

The nation also needs funds for schools, infrastructure, roads and power, among other things, he said.

"For the foreseeable future, the government will need international assistance simply to cover its payroll -- teachers, police, doctors and nurses, civil servants and basic services," Ban said.

More than 200,000 people died in the 7.0-magnitude earthquake, and large portions of the capital city were destroyed.

The U.N. chief lauded international efforts to provide support. He assured Haitian President René Préval's administration that he will also work to fulfill the needs of underfunded programs such as early recovery and agriculture.

But maintaining solidarity after the donors' conference and beyond is a challenge, he said, and so is the situation on the ground.

"We will continue to expedite this process before the rainy season and the hurricane season arrive," he said. "We are a little behind schedule, but any fully effective coordination to provide humanitarian assistance to such a large number of displaced persons has always been a great challenge."