The Labour Party leader Phil Goff has warned that the war in Afghanistan could be turning into another Vietnam.
Mr Goff has repeated his opposition to SAS troops fighting in Afghanistan, saying the war there is not going well.
The United States commander in Afghanistan has admitted that the situation for international forces fighting the Taliban is dire, and says tens of thousands more troops will be needed.
"That's reminiscent of of the days of the Vietnam war, when all we need to do to win this war is send thousands of troops in," Mr Goff says. "The truth is, the war is not going well."
Mr Goff describes the current Afghan regime as "endemically corrupt", a criticism also levelled by the Green Party, which is questioning why New Zealand troops are risking their lives to support a corrupt administration.
Regime's 'very backward' attitude to women cited
Prime Minister John Key announced Monday that SAS troops had arrived in Afghanistan and 71 of them were being deployed - the first deployment there since the Labour Government withdrew SAS troops in 2005.
Green Party defence spokesperson Keith Locke has criticised the deployment, saying: "Why should our soldiers be risking their lives to support a corrupt regime which is in alliance with provincial warlords and has a very backward attitude - to say the least - to women?"
But Mr Key says the Government is supporting the regime in an effort to try to stabilise Afghanistan.
He says he's received no official advice over concerns relating to the recent presidential election, which has been mired in allegations of fraud, but he has read media reports.
The troops will be under the control of the commander of the NATO international security assistance force in Afghanistan, but overall command will be retained by the chief of the New Zealand Defence Force, through an SAS commander in the field.