Rwandan prosecution lawyers called for 22-year jail sentences Wednesday against two senior military figures on trial for inciting rebellion against the central African nation's strongman, President Paul Kagame.

Both men, once close to Kagame's inner circle, former presidential guard chief and serving colonel, Tom Byabagamba, and retired brigadier-general Frank Rusagara, were arrested in August 2014.

They were charged with inciting rebellion by "spreading rumours" and "tarnishing the image of the country and government". They deny all charges.

"They should be punished with 22 years in jail," military lawyer Faustin Nzakamwita said.

According to military prosecutors, the pair had attempted to turn military officials against the government, while Rusagara had been relaying "propaganda" from the dissident Rwanda National Congress (RNC), an exiled opposition group that includes several former top members of Kagame's ruling Rwandan Patriotic Front (RPF).

The prosecutor said Rusagara had been heard saying Rwanda "is a police state and a banana republic", and that he had described Kagame as a "dictator".

For his part Byabagamba had allegedly said that the FDLR, a Hutu extremist group based in Democratic Republic of Congo that includes former 'genocidaires', was no longer a major threat to the country.

Critics of Kagame, however, say the trials expose the workings of a paranoid state that is increasingly nervous over the activities of the RNC.

A co-founder of the RNC, Rwanda's former intelligence chief Patrick Karegeya, once a comrade-in-arms of Kagame's, was murdered on New Year's Eve 2013 in Johannesburg.

Prosecutors have also called for a six year sentence for Rusagara's driver, Francois Kabayiza.

The trial continues.