OTTAWA (AFP) - Federal police swept in and closed the streets around Canada's parliament on Wednesday as they investigated a "suspicious incident", authorities said in a statement.

The lockdown comes hours before Canadian Governor General David Johnston is to give a speech outlining the government's upcoming legislative agenda, and marking the start of a new parliamentary session.

Ottawa police said "that Wellington Street is closed in both directions from Elgin Street to O'Connor Street while police investigate a suspicious incident in the 0-100 block of Wellington".

No other information was provided by authorities, but public broadcaster CBC, citing unnamed police sources, said Parliament had been evacuated and that a man had been arrested.

Authorities were also said to be looking into a suspicious package left outside the office of Prime Minister Stephen Harper, directly across from Parliament.