The politically charged breach of trust trial of one of the military's most senior leaders is set to run through most of the next federal election.

Vice-Admiral Mark Norman and his high-profile lawyer Marie Henein were allowed to schedule the seven- to eight-week criminal trial to start next August, even though a judge told them an earlier date was possible.

Opposition Conservatives and Norman's supporters, which include numerous former military personnel, have accused the Liberal government of political interference in the case, with some suggesting Norman has been charged unfairly.

Henein says the August timeframe was necessary to allow for proper court procedures to play out.

She adds that she has been having trouble getting access to government documents related to the case, which the Liberals classify as cabinet secrets.

Norman was suspended as the military's second-in-command in January 2017 and charged with one count of breach of trust earlier this year for allegedly leaking the Liberal government's decision to pause and review a multimillion-dollar shipbuilding project for the navy in November 2015.

The secrets were allegedly leaked to Quebec-based Davie Shipbuilding in what the RCMP has suggested was an attempt to pressure the Liberals into continuing the project.