Lawyer Douglas Coltart told AFP that state prosecutors had conceded that allegations against him and his colleague Tapiwa Muchineripi do not add up to a criminal offence.
"We should have never been arrested in the first place," he said. "They were overzealous to arrest lawyers who were simply doing their job."
The pair were charged with obstructing justice last year, while representing two opposition members who were recovering in hospital after having been allegedly abducted and tortured.
Coltart and Muchineripi objected to their clients being quizzed by police, arguing they were medically unfit.
But police characterised the exchange as obstructing justice.
A few days earlier the clients had been handcuffed, tasered, beaten with truncheons, drugged and later dumped naked near a river, according to rights groups.
The leading opposition party at the time said the abductors were suspected state agents.
The kidnappings came amid what the opposition said was a campaign of intimidation against its members that followed a disputed election in August that saw President Emmerson Mnangagwa of the ruling ZANU-PF win another term in power.
Coltart said he and Muchineripi have good grounds to sue the authorities and will be deciding the next steps.
Charges Dropped Against Top Human Rights Lawyers in Zimbabwe
HARARE - Zimbabwean authorities on Friday dropped charges against two leading human rights lawyers who were arrested in September after objecting to police questioning their clients in hospital.
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