The BBC's defence correspondent Caroline Wyatt said the Snatch vehicles had become known by troops in Iraq as "mobile coffins".
A former member of the Royal Green Jackets who served in Iraq, Steve McLoughlin, told BBC Radio Five Live that the issue needed much more attention.
"You drive over a landmine in a very-lightly armoured Land-Rover Snatch - it's not much different from driving over it in a Ford Escort.
"At the very least you're going to lose limbs - horrific injuries if you survive - you're probably going to get killed outright.
"The government doesn't like talking about this issue. They get some faceless MoD bureaucrat to issue a two-line statement, then it's gone and forgotten."
Troops have called the Snatch Land Rovers "mobile coffins"
Conservative MP Patrick Mercer told the BBC there had been "at least two ringing reassurances from the government" that Snatch Land Rovers would be withdrawn from patrol duties.
"It is outrageous that these vehicles still remain in service. That soldiers, sailors and airmen's' lives are being put at risk by vehicles that are simply inadequate for these sorts of duties," he said.
Amyas Godfrey, from the Royal United Services Institute, said: "The problem with the Snatch Land Rover is that it was specifically designed for Northern Ireland and it has been adapted and reused for all sorts of different theatres that we never knew we were going to get involved in.
Those responsible should hang their heads in shame
Coroner Andrew Walker, criticising a lack of military equipment
"So, fundamentally it's a capable vehicle, but just not designed for where we are now."
This week, Defence Secretary John Hutton announced an extra £700m for 700 new armoured vehicles for Afghanistan.
The MoD said in a statement: "The events of 17 June were a tragedy and our sympathies are with the families.
"Equipping our personnel is a clear priority and we are absolutely focussed on providing them with a range of vehicles that will protect them from the ever-shifting threats posed by the enemy."
Shadow defence secretary Liam Fox said it was the responsibility of the government to minimise the risks to troops on the frontline
"Gordon Brown's unwillingness to fund Tony Blair's war in Iraq has led to chronic misalignment between resources and commitments," he said.
Liberal Democrat defence spokesman Nick Harvey said the £700m investment in new armoured vehicles had come "tragically late".
"Many voices have been warning about the inadequacy of our vehicles in Afghanistan," he said. "The government should have acted very much sooner."
Earlier this month, military resourcing was fiercely criticised by the coroner at the inquest of Cpl Mark Wright who died after the wrong helicopter was sent to rescue him from a minefield in Afghanistan.
"That a brave soldier is lost in battle is always a matter of deep sadness but when that life is lost where it need not have been because of a lack of equipment and assets, those responsible should hang their heads in shame," Andrew Walker said.
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