Spiwe Vera and Elizabeth Banda were apprehended just days after four aides to Prime Minister Morgan Tsvangirai and their lawyer were arrested on the day the country held a key referendum on a new constitution.
"They (Vera and Banda) took statements and there are no charges against them," said Tsvangirai's spokesperson, Luke Tamborinyoka.
"The interrogation is becoming senseless and we are now taking it as harassment … One of the staffers was called to report again to the police while picking up a child from school," he added.
On Sunday, Thabani Mpofu – director for research in the prime minister's office – and three other colleagues were arrested.
Their lawyer Beatrice Mtetwa, a prominent human rights attorney who has represented the opposition and rights activists, was also detained.
The four aides to Tsvangirai have been charged with breaching the state secrecy code and impersonating the police.
Mtetwa faces a charge of obstructing the course of justice for allegedly shouting at police during a raid of the prime minister's communications office.
All of them were on Wednesday denied bail at a magistrate's court.
After largely voting in favour of the new constitution in the weekend referendum, Zimbabwe will go to the polls later this year to end a shaky power-sharing government between veteran president Robert Mugabe and arch-rival Tsvangirai. – Sapa-AFP.