Tasmanian Australia Post workers yesterday joined their mainland counterparts and went on a 24-hour strike in a bid for better working conditions.

A union spokesman said that hundreds of Australia Post employees across the state did not turn up for work yesterday.

The union expects that the strike will cause a backlog of millions of items at sorting centres in Victoria, potentially impacting the delivery of Christmas mail in Tasmania, although Australia Post denies there will be any delays.

The union apologised for any inconvenience to the community but said that it was a necessary step that had to be taken.

About 400 Australia Post workers marched through Melbourne's CBD to the company's headquarters and vowed to ramp up industrial action in the new year.

Workers are calling for Australia Post to protect full-time jobs and penalty shifts, as well as end the use of company-paid doctors whom they allege are forcing sick and injured employees back to work.

Australia Post managers and casual staff continued to work through the strike covering the workload of full-time employees.

One Launceston post office manager said that ordinary mail that was sent from Sydney on December 21 had arrived in Tasmania today and was being delivered.