Military training was “not as good as it should have been” when four soldiers, including one from Kidderminster, were killed in Afghanistan in 2008, armed forces minister Bill Rammell said.
But he said changes had been made since then and argued vehicles used by British service personnel are the “best anywhere in the world”.
His comments came after an inquest into the deaths of Corporal Sarah Bryant, 26, the first female casualty in Afghanistan, and three special forces comrades heard a string of criticisms over their equipment and training.
Wiltshire and Swindon Coroner David Masters pledged to raise his concerns with the Ministry of Defence at the end of Tuesday’s inquest.
The coroner recorded unlawful killing verdicts for Cpl Bryant and special forces reservists Corporal Sean Robert Reeve, 28, Lance Corporal Richard Larkin, 39, of Cookley, near Kidderminster, and Private Paul Stout, 31, who died when their Snatch Land Rover hit a roadside bomb in June 2008.
The six-day inquest into the deaths, held at Trowbridge Town Hall, heard soldiers had not been shown how to use metal detectors in the UK due to an equipment shortage.
Mr Masters also highlighted the limitations of Snatch Land Rovers.
Mr Rammell said: “The coroner has made serious and searching questions of the Ministry of Defence and particularly of our training regime that existed at the time.
“The hand-held devices were available and were on this vehicle but I accept that the training regime was not as good at that stage as it should have been.
“I would want to make clear that this was at a stage in 2008 when the Taliban were changing tactics to the all-pervasive threat that we face today from improvised explosive devices.
“In response to that we have hugely changed.”
He said £1.7 billion had been spent on 1,800 “new and better protected vehicles”, describing it as “a transformation of the way that we respond to IEDs”.
Mr Rammell defended the use of the Snatch Land Rover, saying: “Given the size and scale of this improvised explosive device that the Taliban planted that killed our soldiers, it was of such a scale that it would have caused devastating impact on any of the vehicles that we had in Afghanistan at that stage.”