YANGON, Myanmar -- A Myanmar junta court on Wednesday rejected an appeal by ousted leader Aung San Suu Kyi against a five-year sentence for corruption handed down last week, a junta spokesman told AFP.

Since a coup ousted her government in February last year, plunging Myanmar into upheaval, Suu Kyi has been in military custody and faces a raft of charges that could jail her for more than 150 years.

Last week the Nobel laureate was convicted of accepting a bribe of $600,000 cash and gold bars -- a charge she said was "absurd", according to her lawyer.

The junta's "Union Supreme Court rejected the appeal of her sentence," junta spokesman Zaw Min Tun told AFP.

Suu Kyi will challenge the latest decision in a higher court, a source with knowledge of the case told AFP after the ruling.

She had "decided to continue till the end of the process to check the situation of the rule of law here," the source said.

There was no date given for the fresh appeal, which will be heard in the Union Supreme Court in front of two judges.

Before her corruption conviction, the 76-year-old Suu Kyi had already been sentenced to six years in jail for incitement against the military, breaching Covid-19 rules and breaking a telecommunications law.

Appeals against those convictions are currently pending in the courts, the source said.

Suu Kyi will remain under house arrest at an unknown location in the military-built capital Naypyidaw while she fights other charges.

She faces a raft of other trials, including for allegedly violating the official secrets act, several counts of corruption and electoral fraud.

Journalists have been barred from attending the court hearings and Suu Kyi's lawyers have been banned from speaking to the media.

- 'Sport in a court' -
The rejection of the appeal marked "another stage in the show trial," David Mathieson, an independent analyst working on Myanmar, told AFP.

"This is sport in a court, a form of mental cruelty."

Under a previous junta regime, Suu Kyi spent long spells under house arrest in her family's colonial-era lakeside mansion in Yangon, Myanmar's largest city.

Today, she is confined to an undisclosed location in the capital, with her links to the outside world limited to brief pre-trial meetings with her lawyers.

The junta has rebuffed requests by foreign diplomats to meet Suu Kyi while she is on trial.

The coup last year sparked widespread protests and unrest that the military has sought to crush by force.

Fighting has flared with established ethnic rebel groups in border areas and across the country "People's Defence Forces" have sprung up to fight junta troops.

According to a local monitoring group, the crackdown has left more than 1,800 civilians dead while over 13,000 have been arrested.

Suu Kyi has been the face of Myanmar's democratic hopes for more than 30 years, but her earlier sentences already mean she is likely to miss elections the junta has said it plans to hold by next year.