At least four people have been killed in Chad's capital of N'Djamena as security forces claimed to have foiled an attempted coup against President Idriss Deby's government.

A number of arrests were made, among them opposition coalition MP Saleh Makki of the Co-ordination of Political Parties for the Defence of the Constitution (CPDC) and members of the military.

"A group of individuals with bad intentions sought to carry out an action to destabilise the institutions of the republic," communications minister Hassan Sylla Bakary said.

"They did not count on the valiant security forces who have tracked them since December 2012 and who neutralised them."

A police source told Reuters that between four and eight people were "killed in fighting at a military barracks in the east of N'Djamena".

Makki's wife, Flmata Saleh, confirmed that her husband was among those apprehended. she said he was not guilty of involvement in the coup plot.

"He called me to say that he had been arrested," Saleh said. "Outside the house there were a lot of police with two vehicles.

"They went into the courtyard and they took him with them. I know my husband well and he wouldn't do this. He didn't do anything. We are waiting to see what they are going to say."

Deby recently accused Libya of allowing Chadian mercenaries to set up a training camp just across the border but Tripoli denied his claims. Deby said the group aimed to destabilise his government.

Earlier this year Deby sent 2,000 troops to support French forces battling Islamist rebels in Mali but pulled them after announcing they did not have "the skills to fight a shadowy, guerrilla-style war".