Myanmar's junta on Monday expressed its 'utmost indignation' at a French diplomatic snub describing it as an illegitimate government, warning it could threaten bilateral ties.

Last week the junta said it would execute a former lawmaker from Aung San Suu Kyi's ousted party and a prominent democracy activist, in what would by the country's first judicial executions in decades.

The announcement sparked outrage among rights groups and governments and calls for their release.

A statement condemning reports of the sentencing issued by France's embassy in Yangon also referred to the junta as an 'illegitimate military regime.'

On Monday the junta's foreign affairs ministry expressed 'its utmost indignation and strong protest.'

The remarks were 'totally unacceptable to the Government of Myanmar... this statement could have negative impacts on the existing bilateral relations,' it said in a statement.

Western governments have led international criticism of last year's coup that ousted Suu Kyi's administration and unleashed a violent crackdown on dissent, with some imposing sanctions and meeting with opposition figures.

The statement also slammed the United States State Department and the spokesman of the United Nations Secretary-General for their 'irresponsible and reckless statements' on the case.

In May the junta threatened to downgrade diplomatic ties with Australia after it said Canberra would not replace its recently-departed ambassador to the military-run country.

Britain's recent downgrading of its mission in the country to charge d'affaires was also slammed as 'unacceptable' by a spokesman last month.

Shunned by Western governments, the junta has turned to traditional allies, including Russia and China for support.

It has described Russia's invasion of Ukraine as 'justified,' backing its major ally and arms supplier.

Four people, including former MP Phyo Zeya Thaw and democracy activist Ko Jimmy, will be hung after their appeals against their death sentences were thrown out, a junta spokesman said on Friday.

The date for the executions has not yet been announced.

The junta has sentenced dozens of anti-coup activists to death as part of its crackdown on dissent after seizing power last year, but Myanmar has not carried out an execution for decades.