Malawi's Anti-Corruption Bureau has summoned ex-president Bakili Muluzi to a hearing about his financial dealings with foreign donors next week.
Mr Muluzi has fallen out with the new president
It intends to ask him what happened to millions of dollars of aid during his rule, which ended last year.
The announcement came as parliament renewed its drive to impeach current President Bingu wa Mutharika.
Mr Muluzi's supporters say Mr Mutharika is mounting a witch-hunt against his predecessor, after the two fell out.
Handpicked by Mr Muluzi, President Mutharika quit the United Democratic Front (UDF) earlier this year, saying the party disliked his tough anti-corruption drive that has seen many senior officials, including some former ministers, arrested.
On Tuesday, parliament passed the first laws which will enable impeachment procedures to proceed.
The UDF say they want the president impeached for violating the constitution and misusing government funds.
International donors have urged the president's critics not to go ahead with impeachment, saying political in-fighting is distracting attention from the food crisis in Malawi.
Over the weekend the president declared a national disaster over the food shortages after the worst harvest in a decade.
The United Nations says some 5m people - nearly half the population - may need aid.