Bruce Carson is scheduled to appear in the Ontario Court of Justice for a five-day trial, beginning July 22.
An agent for Carson's lawyer said Monday that, by setting a trial date, Carson has pleaded not guilty to a charge of fraud on the government, also known as influence peddling.
The Prime Minister's Office contacted the Mounties in March 2011 with allegations that Carson had illegally lobbied the federal government.
Carson was an adviser to Harper from 2006 to 2008.
Lawyer Pat McCann maintains his 66-year-old client will vigorously defend himself.
Concerns about possible impropriety were first raised by the Aboriginal Peoples Television Network.
It reported that Carson had allegedly lobbied Indian and Northern Affairs on behalf of an Ottawa-based water company that employed his girlfriend
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