Rod Kirkpatrick states that the Gippsland Mercury was launched by Alexander Britton 'at Sale on November 1, 1869, using the presses of Gippsland's earliest newspaper, the Gippsland Guardian, which had closed four months earlier. Britton had been the editor of the Guardian.' (Source: Rod Kirkpatrick, 'A Sale Where Sometimes You Pay, and Sometimes You Don't', UQ eSpace (October 2005): 48-49)
Other sources, including the State Library of Victoria, provide1860 as the newspaper's start date.