More than 1 million people still don't have adequate food, water or shelter a month after a devastating cyclone swept through Burma, also known as Myanmar, and it's not clear what the military junta is doing to help them, the United Nations said Tuesday.

Humanitarian groups say they continue to face hurdles from Burma's military government in sending disaster experts and vital equipment into the country. As a result, only a trickle of aid is reaching the storm's estimated 2.4 million survivors, leaving many without even basic relief.

Aid groups are unable to provide 1.3 million survivors with sufficient food and clean water, while trying to prevent a second wave of deaths from malnutrition and disease, the U.N. said in its latest assessment report.

Of the 1 million people who are getting help, most have been "reached with inconsistent levels of assistance," the U.N. said.

"There remains a serious lack of sufficient and sustained humanitarian assistance for the affected populations," the report said.

It also said the world body lacked "a clear understanding of the support being provided by the Government of Burma to its people."

It's shocking that cyclone victims still need basic relief after four weeks, said Sarah Ireland, regional director of the British aid organization Oxfam, which is trying to get permission to work in Burma.

"If we were in a normal response by week four, those affected should be working toward recovery," she said Monday. "They would be in a position perhaps to think about what they need to restart their lives. But we know people on the ground don't have food to eat."

Tidal surges as high as 12 feet reached some 25 miles inland as the cyclone churned through the country for two days beginning May 2. The storm laid entire villages in the Irrawaddy delta to waste and left 78,000 people dead and another 56,000 missing, according to the government's count.

But the relief has yet to match the scale of the disaster.

A big obstacle in providing relief has been reaching the delta. With only seven government helicopters operating, most relief supplies are being transported along dirt roads and by boat. Vessels able to navigate the debris-filled canals are scarce and efforts to import trucks and other vehicles have been hampered by governmental red tape.

"For aid agencies it is very important that those affected receive a full complement of appropriate aid," said James East, a spokesman for World Vision, a private aid agency operating in Burma even before the disaster. "To say that a certain percentage of people have received aid means little because some survivors may have received a tarpaulin but no food and vice versa."

Stories have emerged of survivors going days without food or being forced to drink from dirty canals. The Associated Press has interviewed survivors in recent days who still have not received any government or international assistance and turned to the country's revered monks for help.

Human rights groups have also accused Burma's military rulers of kicking homeless cyclone survivors out of camps, schools and monasteries and sending them back to their devastated villages to help restore the country's agriculture sector.

"It's unconscionable for Burma's generals to force cyclone victims back to their devastated homes," said Brad Adams, Asia director at Human Rights Watch. "Claiming a 'return to normalcy' is no basis for returning people to greater misery and possible death."

Burma's xenophobic military regime left survivors to largely fend for themselves. It barred foreigners from the delta until last week and refused entry to U.S. and French aid-laden naval vessels, which have been idling off the country's coast.

The junta's response was in stark contrast to that of Indonesia's Aceh province during the 2004 tsunami and Pakistan during its 2005 earthquake. Both countries allowed in hundreds of international aid groups and set aside their suspicions to let American troops ferry aid and evacuate survivors from remote areas.

The lack of foreign experts in the field has meant a chaotic and uneven aid effort, aid organizations said. Without them, it is nearly impossible to asses needs of survivors or set up systems that would now be in place in a normal disaster response, the groups said.

The International Federation of Red Cross and Red Crescent Societies waited until Monday for government approval to send six foreign experts into the field to help run its water treatment facilities. Until now, it has been able to provide only 5,000 people each day with clean water.

"It was much easier to get medical supplies, clean water, engineers and psychological consultants into the field in Aceh within the first month," IFRC spokesman France Hurtubise said. "Human resources and expertise remain a challenge in Burma."

One small sign of progress was registered Monday: except in the areas most devastated by the cyclone, most schools opened as scheduled at the end of a break that started in March.

In many cases, school buildings were still missing windows and parts of their roofs gone, but UNICEF and other education experts agreed that getting children back to their studies as soon as possible was an important part of the healing process.