Former Zimbabwe President Robert Mugabe is to be summoned by a committee of lawmakers in Zimbabwe to testify at a parliament probe into lost revenue from diamond mining.

The lawmakers plan to question Mugabe over his 2016 claim that the country had lost $15-billion (12.13-billion euros) in income from diamonds due to corruption and foreign exploitation, Kenya’s Daily Nation reported on Wednesday.

Mugabe, who was kicked out of power last year in a military takeover, has previously been accused of siphoning off Zimbabwe’s diamond profits.

"The committee resolved to call the former president to testify," Temba Mliswa, an independent lawmaker who chairs parliament's committee on mines and energy said.

"He was the president, and we want to know where he was getting the $15-billion figure from."

No date has been set for the hearing and it remains uncertain if the aging former dictator, now 94, will ultimately face a grilling from lawmakers.