Some state Labor ministers could face a loss in superannuation benefits when the party goes into opposition.

This is because part of a Queensland's MP's super is based on the average of their total career salary, a statistic which would drop for ministers who move to the opposition backbenches.

One likely casualty is current Deputy Premier Tom Burns, who faces a loss in his career average salary while attracting no increased benefit for continued service because he has been in parliament for over 20 years. Mr Burns entered parliament in 1972.

Parliament's superannuation scheme is based on a current backbencher's salary of around $78,000. A member is entitled to 50 percent of this annually after 8 years of service to a maximum 80 percent annually after 20 years service.

This is then bolstered by averaging the MP's salary over his or her career. A minister who has averaged, say, 20 percent more than a backbencher's salary over a career will be credited with 20 percent more superannuation.

Under this system, MPs with short parliamentary careers spent mostly in the ministry could also suffer, because their average salaries would drop sharply.

Members can either receive an annual salary or take 10 times the amount as a lump sum.

Of course, Labor MPs would not suffer a net decrease in benefits should any increase in a backbencher's salary offset any career average loss.