Bennett, an ally of Prime Minister Morgan Tsvangirai, was arrested in February and charged with possessing weapons for purposes of terrorism, insurgency and banditry, charges which carry a potential death sentence upon conviction.
The case has raised tensions in a fragile unity government formed by President Robert Mugabe and Tsvangirai, whose Movement for Democratic Change says the trial is political persecution.
On Thursday, defence lawyer Beatrice Mtetwa said police had brought to court licensed weapons belonging to Peter Hitschmann, who prosecutors say implicated Bennett when the registered arms dealer was arrested for possessing dangerous weapons in 2006.
Hitschmann was jailed for illegally possessing six sub-machine guns, a pistol and two machineguns but the court threw out the more serious terrorism charges against him and also found that he had licences for most of the weapons.
Mtetwa said police in Bennett’s case had added several other guns, anti-riot grenades, stun grenades and thousands of rounds of ammunition, whose origins could not be established and were never produced in the trial of Hitschmann, an accomplice witness in Bennett’s trial.
Bennett is accused of paying for weapons found in Hitschmann’s possession.
"This is part of a police publicity stunt to whip up public sentiment and misrepresent facts to this court," said Mtetwa.
Mtetwa also accused police of failing to document weapons found in Hitschmann’s possession and that they were stored at an army barracks, making it possible that more weapons could have been added to strengthen the state’s case.
Hitschmann says he was tortured into implicating Bennett. He later recanted his confession in the presence of his lawyer.
Hitschmann, who was a policemen during white minority rule when Zimbabwe was known as Rhodesia, has also written to the attorney general saying he was not prepared to testify against Bennett because he had no evidence to give.
Mtetwa said Hitschmann had been tortured while in the custody of central intelligence operatives and the army.
State witness Sipho Makone, a senior police officer, denied the torture charges. The trial continues.