A Myanmar junta court sentenced ousted leader Aung San Suu Kyi to three years in jail for electoral fraud during 2020 polls her party won in a landslide, a source with knowledge of the case said Friday.

Suu Kyi was "sentenced to three years imprisonment with hard labour", the source said, adding that the Nobel laureate, 77, appeared to be in good health.

Detained since the putsch last year, Suu Kyi has already been convicted of corruption and a clutch of other charges by a closed junta court and sentenced to 17 years in prison.

The military alleged widespread voter fraud during the November 2020 election, won resoundingly by Suu Kyi's National League for Democracy (NLD) party, although international observers said the poll was largely free and fair.

The military has since cancelled the result and said it uncovered more than 11 million instances of voter fraud.

In a speech broadcast last month, Min Aung Hlaing did not mention a date for fresh polls but said they could only be held when the country was "peaceful and stable".

More than 2,200 people have been killed and over 15,000 arrested in the military's crackdown on dissent since it seized power, according to a local monitoring group.