Myanmar's de facto leader Aung San Suu Kyi has been forced to take a rest from her state duties after becoming unwell during a state trip abroad, her office said Monday.

The 71-year-old was diagnosed with gastritis after returning from a visit to Britain and the US, her first trip to her Western allies since taking office in March.

Pictures of her being pushed through Yangon airport in a wheelchair posted on social media sparked concern about the Nobel Laureate's health and quickly went viral.

"She feels weak as she did not have much time to rest during the trip," her office said in a statement.

"She has a stomach ache as she did not have time to have regular meals," it added, adding that she "just needs to rest for a while".

Suu Kyi's health has long been a topic of speculation in Myanmar, where she is deeply revered after decades leading the struggle against the former military junta.

Since her release in 2011 from long years under house arrest she has kept a notoriously frenetic schedule despite her advanced years and slight frame.

But occasional bouts of ill health stopped her campaigning in 2012 and forced her to cancel public appearances last year. Earlier this year she also had operations to remove cataracts from both eyes.

Suu Kyi holds several key cabinet positions including foreign minister, as well as leading the government in a specially created role of state counsellor.

Many of her government cabinet members are also fellow democracy veterans of advanced years, leading a country with an otherwise burgeoning youth population.

Her doctor, Tin Myo Win, said he was "very busy with the health of Aung San Suu Kyi" when briefly reached by AFP, but declined to give further details