The charges against Bennett, which his party, the Movement for Democratic Change, says were "trumped up", are linked to a confession by arms dealer Peter Michael Hitschmann.
Bennett's lawyer, Beatrice Mtetwa, says she has Hitschmann's affidavit in which he disowns his earlier "confession" implicating Bennett.
The dealer says his confession was obtained through the use of torture.
The judge turned down a request by Mtetwa to bar the prosecution from calling Hitschmann as a witness.
Judge Bhunu said the allegations that Hitschmann was tortured could be tested in court when he testifies.
Bennett, the MDC treasurer and designated deputy agriculture minister, quietly followed the court proceedings. He seemed to be in good spirits, even though he could face death if convicted.
The state alleges that in 2006 an arms cache was discovered at a house in Mutare, a city in the east of Zimbabwe. The state claims subsequent investigations linked Bennett to the crime.
The trial continues.
mcritic