Zambia's ex-president Rupiah Banda asked the country's High Court Thursday to stop parliament from considering a motion to strip his immunity, on the eve of a debate planned by lawmakers loyal to his successor.
Banda, who bowed out of power after losing elections to current President Michael Sata in 2011, said he had not been given a chance to defend himself, and that while in office he had acted in an official and not a personal capacity.
In papers filed by his lawyers, Banda asked the High Court to rule that "the executive cannot lay before the national assembly and debate grounds or charges for lifting my immunity without giving me an opportunity to be heard.
"The executive cannot lay before the national assembly for debate grounds or charges of lifting my immunity that relate to duties that I did undertake in my official capacity and not in my personal capacity," he added.
Banda also said he had not been given "adequate time and facilities to prepare a meaningful defence to the charges".
The former president faces graft allegations, which his lawyers say are part of a political ploy by Sata to purge any and all opposition.
The court case came after AFP obtained a parliamentary order paper showing that Justice Minister Wynter Kabimba planned to present a motion to parliament on Friday to strip Banda of his presidential immunity.
"Mr Rupiah Bwezani Banda who has held, but no longer holds the office of the president may be charged with any criminal offence," the motion reads.
It would allow charges to be brought for crimes committed during Banda's time in office as long as prosecution would "not be contrary to the interests of the state."
If allowed to go ahead, the motion would be certain to receive the support of Sata's Patriotic Front, which holds more than a third of the seats in the 158-member parliament.
Banda's peaceful handover to Sata was hailed at the time as an example of a smooth transfer of power in Africa's largest copper producer.
But Sata's government has since arrested a number of opponents, raising fears the country is sliding toward authoritarianism.
Opposition leaders and former ministers have been arrested in recent months for an array of offences said to have been committed while they were in office.
Amid the spate of arrests, the opposition has launched a campaign for Zambia to be expelled from the Commonwealth.
On Wednesday Sata personally warned foreign diplomats against engaging with the opposition on governance issues.
"What I will not accept is you touring provinces and asking the opposition parties about governance issues," Sata told 14 foreign envoys presenting their credentials in the capital.
"If you want to ask about governance issues come to my office or go to the ministry of foreign affairs."
Among those present were the ambassadors of Canada, Ireland, South Africa, Kenya, Israel, New Zealand and South Korea.
Watchdog Transparency International has supported calls for lifting Banda's immunity so he can answer the charges against him.
But Banda's lawyer Sakwiba Sikota called the motion a "total mockery of justice", saying his client had not been charged or given a chance to defend himself.
"How can they think of removing his immunity without any charges? The people that were preparing the same indictment are not serious," he told AFP.
"This is a serious constitutional matter and I expect members of parliament to debate intelligently."
Late Zambian leader Fredrick Chiluba, who ruled from 1991 to 2001, had his immunity removed after his hand-picked successor Levy Mwanawasa presented parliament with numerous charges against him.