Bill Shorten's chief spin doctor, Kimberley Gardiner, is leaving the Opposition Leader's office by mutual agreement following an internal review ahead of the next election.

In a move that will be interpreted as the Opposition Leader looking to sharpen his political messaging and re-connect with voters in 2016 after falling well behind Prime Minister Malcolm Turnbull in the opinion polls, Ms Gardiner is leaving the role of communications director after more than three years working for Mr Shorten.

The review of Mr Shorten's office was undertaken by chief of staff Cameron Milner, a former Queensland Labor state secretary who replaced Ken Macpherson as chief of staff in September last year.

Ms Gardiner was a long serving staffer to Julia Gillard when she was deputy prime minister and worked for Mr Shorten when he was a minister in the former Labor government as well as in opposition. She has clocked up almost a decade of service in total with the ALP, including time with former Queensland premier Anna Bligh, as well as for AFL club St Kilda.