Government forces in the troubled Central African Republic have arrested a rogue ex-rebel commander, the justice minister told AFP Friday, as Bangui tries to clamp down on warlords.

Since Michel Djotodia seized power in a March coup, some ex-rebels from his now-dissolved Seleka group have integrated the regular army but others went rogue and have been sowing terror.

"Seven criminals, led by a so-called colonel going by the name of Mahamat Amine and who had emerged from the bush in Damara, were detained by our security and defence forces," Justice Minister Arsene Sende said.

Damara lies around 75 kilometres (45 miles) north of the capital Bangui. The rogue colonel and six of his men were arrested on Wednesday, the minister said.

On the same day, another ex-Seleka warlord known as "Colonel Abdallah" who had been ruling over the eastern town of Bangassou was arrested together with four of his lieutenants and transferred to Bangui, officials said.

"The chief prosecutor and the main police investigations department are sparing no effort in bringing those criminals to justice," Sende said.

The impoverished landlocked country is a little larger than France but sparsely populated and Djotodia is facing the same difficulty as his predecessors in extending his authority beyond the capital.

Chaos followed the ouster of Francois Bozize earlier this year and reports of summary executions, looting and abuses against civilians have prompted international concern that the Central African Republic could become another Somali-style failed state.