Four days after the shallow 7.7-magnitude earthquake struck, humanitarians are struggling to deliver assistance, with mounting fears that attacks and obstruction could hinder the aid effort.

The United Nations humanitarian agency however insisted it was not seeing signs of intentional blockage.

"So far, we have been able to provide assistance to the people," said Marcoluigi Corsi, the UN resident humanitarian coordinator in Myanmar.

"The distribution of different items is ongoing and we haven't experienced so far any blockage," he told reporters in Geneva, speaking via video link from Yangon.

Myanmar's junta said Monday 2,056 people had been confirmed dead, with more than 3,900 injured and 270 missing. At least 20 people died in neighbouring Thailand.

But the toll is expected to rise significantly as rescuers reach towns and villages where communications have been cut off by the quake.

"The destruction is immense... The needs are massive and they are rising by the hour," Julia Rees, deputy Myanmar representative for the UN children's agency UNICEF, told reporters, also speaking from Yangon.

"The window for life-saving response is closing, and across the affected areas, families are facing acute shortages of clean water, food and medical supplies," she warned.

- Stop attacks -

Even before the earthquake, nearly 20 million people in Myanmar needed humanitarian aid, including more than 6.5 million children, according to UN figures.

Corsi said the UN estimates more than 3.5 million people were already internally displaced in Myanmar, with fears that number could swell beyond five million this year.

Complicating recovery efforts is the country's brutal ongoing civil war, sparked in 2021 when a military junta ousted Aung San Suu Kyi's civilian government.

Since then, fighting between the military and a complex patchwork of anti-junta forces has left Myanmar's infrastructure and economy in tatters.

Allegations that the junta has continued using air attacks since the quake have triggered sharp criticism, including from the UN special rapporteur for Myanmar, Tom Andrews, who called for the military attacks to stop.

The UN refugee agency said its team on the ground was seeking to identify the most critical needs in the worst-affected areas, highlighting the dire need for shelter.

Spokesman Babar Baloch also warned of the "risks around explosive ordnance" likely buried in quake-hit areas.

"Family separation, child protection and gender-based violence" also needed to be monitored he added.

The International Federation of Red Cross and Red Crescent Societies (IFRC) meanwhile warned that soaring temperatures of up to 40 degrees Celsius (104 Fahrenheit) were making the situation worse.

It has appealed for 100 million Swiss francs ($113 million) to support around 100,000 people in affected areas.

Humanitarian aid to Mynanmar has been "chronically underfunded for years", said Corsi, with less than five percent received of the $1.1 billion the UN has requested this year.