Economist Sean Turnell was the first foreign national arrested following the February 1 coup that ousted Aung San Suu Kyi from power.

The State Administrative Council -- as the junta calls itself -- has charged Turnell with breaching the official secrets laws.

Held at the notorious Insein prison since his arrest, Turnell is now experiencing "cold and flu symptoms", his wife Ha Vu said on her Facebook account.

"The Delta variant has reached Insein... his health is at tremendous risk," she wrote.

Turnell's father was also recently diagnosed with cancer, she said, calling for authorities to allow him to return to Australia on "compassionate grounds".

"He is very anxious for whatever the misunderstanding it might be to be resolved quickly. This is his plea!"

Myanmar -- which has seen daily anti-junta protests since the coup -- is currently experiencing a surge of Covid-19 cases.

Staff in cemeteries and crematoriums are overwhelmed as growing numbers of bodies of virus victims are brought for their services, while desperate relatives queue in long lines for oxygen for their ailing family members.

So far, the country has officially registered 229,521 novel coronavirus cases and 5,000 deaths.

But the number is likely far higher, with reports of ambulances being turned away from hospitals that are at capacity.