* Military goes ahead with constitutional referendum

* U.N. appeals for $187 million in aid

* U.N. food agency resumes relief flights

* U.S. says it has approval to send one aid flight

By Aung Hla Tun

YANGON, May 9 (Reuters) - The military rulers of Myanmar went ahead with a constitutional referendum on Saturday despite calls from the outside world to postpone it after the devastation of Cyclone Nargis.

The plebiscite was postponed by two weeks in the hardest-hit Irrawaddy delta and the city of Yangon, but voting went ahead in other parts of the isolated southeast Asian country of 53 million.

State-run TV news repeated Friday's broadcasts urging people to vote, making no mention of the estimated 1.5 million victims of the cyclone without food and shelter or tens of thousands killed and missing in the vicious storm that struck a week ago.

"Those who value the national well-being should go and vote 'yes'," MRTV said in a scrolling headline on the screen.

Even before Nargis, groups opposed to military rule and foreign governments, led by the United States, had denounced the constitution and vote as an attempt by the military to legitimise its 46-year grip on power.

There is even more cynicism after the government's struggle to respond to the disaster about the generals' attempt to proceed with its "roadmap to democracy" meant to culminate in multi-party elections in 2010.

"Will this be voting? I don't think so," said one businessman in Myaung Mya, a town on the fringes of the devastated rice-growing Irrawaddy delta. "They take your name and ID number. Then they know if you give them a tick or a cross."

The government has accepted food, water and equipment from several countries and U.N. agencies, but appeared determined to distribute aid on its own.

Scores of relief experts, accustomed to entering a disaster zone within 48 hours, are still waiting for visas a week after the cyclone washed over the delta with high winds and waves.

ANGUISHED APPEALS

The United Nations appealed for $187 million in aid, even though it is still not confident the food, water and tents flown in will make it to those most in need due the junta's reluctance to admit international relief workers.

During an emergency meeting in New York, dozens of U.N. envoys voiced concern at the difficulties aid workers were having getting in.

But Myanmar's delegate insisted food and other supplies were being sent where needed upon arrival.

"We are ready to cooperate fully," Ambassador Kyaw Tint Swe told the meeting. "Regarding access, we hear you and I will certainly report back to the authorities."

The U.N.'s World Food Programme briefly suspended its aid airlift after it said 38 tonnes of biscuits and medical supplies were impounded at the airport in Yangon, the former capital.

The generals approved one U.S. aid flight, due to arrive as soon as Monday.

"We're going to make as effective use of that flight as we possibly can," U.S. State Department spokesman Sean McCormack said. While the permission was "positive," he said, many more relief runs would be needed to cope with the disaster.

DEATH TOLL

Myanmar has not updated the official toll since Tuesday, when it said nearly 23,000 were dead and 42,000 missing. Even those numbers, which are likely to rise, make Nargis Asia's worst cyclone since 143,000 people died in Bangladesh in 1991.

U.S. charge d'affaires Shari Villarosa has said the death toll could reach 100,000.

With each day that passes, pressure is mounting on the junta to admit a massive international relief operation before starvation and disease swell the death toll even more.

The U.S. Navy is sending ships on exercises in Thailand towards Myanmar, and French Foreign Minister Bernard Kouchner said he was sending a naval ship with 1,500 tonnes of aid to arrive by the middle of next week.

The vessel, Le Mistral, is capable of carrying heavy-lift helicopters and was the same one used to evacuate French nationals from Lebanon in 2006.

U.N. Secretary-General Ban Ki-Moon urged the junta to accept aid and humanitarian workers "without hindrance," saying the survival of Myanmar's people was at stake.

He said he had so far not been able to contact Myanmar's senior general, Than Shwe, to ask him in person.

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---------------------------------------------------------- (Additional reporting by United Nations, Geneva and Washington bureaux; Writing by Ed Cropley; Editing by Grant McCool)