LIBERAL MP Mal Washer will urge Australia to "get out" of Afghanistan during this week's parliamentary debate on the mission.

Former Labor defence minister Joel Fitzgibbon will warn that governments need to be "more frank" about the challenges.

While the vast majority of MPs will endorse the mission, the Greens' Adam Bandt and independent MP Andrew Wilkie, a former intelligence analyst, will call for an exit strategy. Mr Wilkie has described arguments that the deployment will protect Australia from terrorism as a "great lie".

Dr Washer said last night: "We should get out as soon as possible. (Hamid) Karzai and his regime (are) notoriously corrupt."

Liberal senator Russell Trood, the deputy chairman of the Senate standing committee on foreign affairs, said the Rudd-Gillard government had "failed abjectly to make a public case for why we are in Afghanistan".

"If they're not prepared to do that, they should withdraw. But I am for staying the course. This counter-insurgency strategy has some chance of winning."

Another former Labor defence minister, John Faulkner, will join the discussion next week, when it reaches the Senate.

Mr Fitzgibbon said last night he strongly backed the deployment, but planned to tackle "reckless statements" by the Coalition in recent weeks that had undermined community support.

Mr Fitzgibbon said he did not believe there was anything Australia could have done to reduce the number of recent troop deaths: "It sounds brutal but the number of deaths is relatively small compared to other nations and compared to Vietnam."