Mr Harkins has lodged an application to form a "non- geographical" branch, which allows members to join from anywhere in the state instead of attending their local branch.

Mr Harkins said the new branch was designed to make it easier for union officials, who travel regularly to sites across the state, to meet.

However, the move is being viewed by some Labor insiders as an indication that Mr Harkins is gathering support to secure preselection ahead of the next Senate election.

Tasmania and the ACT are the only jurisdictions where the Labor Party allows the special branches to exist.

The ALP administrative committee is considering Mr Harkins's application but is expected to reject the move or tighten the rules to block it.

Mr Harkins yesterday would not say if he still held political ambitions.

"At this stage all I'm interested in is defending workers against the federal Liberal government's attacks," Mr Harkins said.

He was forced to withdraw as Labor's candidate in Franklin in 2007 after then-prime minister Kevin Rudd attacked him in Parliament.

Mr Rudd has reportedly since conceded that it was a case of mistaken identity.

Senator Polley is no longer assured her No.1 spot on Labor's ticket since a series of damaging revelations about bullying accusations from her staff.

The Launceston-based Senator is a member of the Labor right and is backed by the Australian Workers Union and the Shop Distributive and Allied Workers Alliance, but they are reconsidering their support.

Senator Polley was investigated by Commonwealth workplace relations body Comcare after three staff had claims - in which they alleged she had bullied and harassed them - approved for compensation.