The opposition alleged that more than a million voters were prevented from casting their ballots in July’s poll.
The polling stations where the violations are alleged to have occurred were mostly in the capital and urban areas considered to be strongholds of the opposition Movement for Democratic Change (MDC).
Australia, along with several other Western countries, had expressed concern at the conduct of the poll, but African monitors praised the election as peaceful, while noting some irregularities.
“Once the elections of 31 July were stolen by the current government, which is illegitimate, I knew that this is the end of the line,” Ms Zwam Bila said.
Ms Zwam Bila, an appointee of former Prime Minister Morgan Tsvangirai, was recalled from her post without being offered another job after the elections.
Ms Zwam Bila said she had been subjected to threats and a “smear campaign”. Mr Tsvangirai belongs to the MDC, as does Ms Zwam Bila.
July’s elections ended a fragile power-sharing government formed by Mr Mugabe and Mr Tsvangirai in 2009.