Exactly a year on from the February 1 military takeover, the United Nations said the economic chaos following the coup had left many unable to feed their families.

The UN estimates that out of 54 million people in Myanmar, 25 million are living in poverty and 14.4 million need humanitarian aid -- including five million children.

Of those, the UN hopes to reach the 6.2 million most severely in need, with a plan that seeks a record amount for the country -- more than twice the money requested last year.

"The economic and political turmoil of 2021, combined with the devastating impact of Covid-19, has driven half the population into poverty," Jens Laerke, a spokesman for the UN's humanitarian agency, told reporters in Geneva.

"Many can no longer afford to feed their families because of job and income losses, and price increases."

Myanmar's military seized power one year ago, ousting the civilian government and arresting its de facto leader, Aung San Suu Kyi.

The UN Human Rights Office said that since the coup, at least 1,500 people had been killed by the military in a brutal effort to crush dissent, while thousands more would have been killed in the wider armed conflict and violence.

- 'Appalling conditions' -

Laerke said more than 400,000 people had been displaced since the coup d'etat.

"Thousands of displaced people are living in appalling conditions, many in camps and displacement sites, others with host communities. And some have crossed the borders with Thailand and India or have sought refuge in the jungle without adequate food, shelter, sanitation, protection or medical care," he said.

He called for humanitarian agencies to be allowed access to displacement sites to deliver life-saving food, water and healthcare.

Ramanathan Balakrishnan, the UN resident and humanitarian coordinator in Myanmar, said the outlook was "grim" and many of the country's gains of the last 15 years were under serious threat.

"2021 has been a traumatic year for the people of Myanmar, characterised by unprecedented levels of human suffering," he said in the document outlining this year's response plan.

"Poverty is back to levels not seen since 2005, with almost half the population now unable to make ends meet."

He said more than 13 million people were now in moderate or severe food insecurity.

"The outlook for malnutrition is dire unless we intervene now," Balakrishnan said.

"People are increasingly resorting to dangerous coping strategies to survive, leading to worsening protection risks."