Marilyn McLaren retired as CEO last February and received a six-figure severance package.
She was soon brought back on a one-year, $50,000 contract.
The government said at the time McLaren's expertise was needed to help her replacement, and to help the corporation's bid for a rate hike before provincial regulators.
The new CEO, Daniel Guimond, told a legislature committee this week McLaren has not done any work under her new contract, and was simply there as a type of insurance policy in case he quit or fell ill.
Opposition Tory legislature member Kelvin Goertzen said Wednesday it is unbelievable that a Crown agency is paying someone to do no work.
"That is not the explanation we were given by the government (at the time), nor do I think it's an explanation that Manitobans think would be good value for dollars," he said.
The minister responsible for MPI, Andrew Swan, said McLaren volunteered Wednesday to end her contract. Since she has worked for roughly six months, that would reduce her payment to about $25,000.
McLaren's contract required her to be available on 48 hours' notice to provide advice and other help, Swan said.
"She has been available and has been prepared, but the management team has decided that it hasn't been necessary. On the one hand, that's something I think we can be happy about; on the other hand, I accept that it raises questions about the value of the contract."
Swan said it's not uncommon for private and public companies to give top executives a severance package and hire them back on contract during a transition period.
"The transition to the new CEO has gone so well ... that they actually haven't had to call upon Ms. McLaren's expertise."