Harriet Harman, the British constitutional affairs minister, said she was seeking a meeting with senior US officials to persuade them to provide live testimony at inquests in Britain.
The move comes after a UK coroner repeatedly commented on the American military's unwillingness to co-operate with inquests in Britain, which are required in law when a British citizen dies abroad and the body is repatriated.
Harman told ITV1 television in an interview on Sunday: "If our service people have died in Iraq, the very least we can do is to make sure there is a proper inquest, so their families can understand the truth of the situation of how their loved ones died.
"We need those American service people and experts to be in the coroner's court in order to give an account of the situation.
"When they don't come that's not acceptable and we are prepared to say that's not acceptable."
"We need those American service people and experts to be in the coroner's court in order to give an account of the situation,"
Harriet Harman, a British minister
Coroner Andrew Walker last month publicly blamed US Marines for the unlawful killing of a British journalist, his Lebanese interpreter and French cameraman in Iraq in 2003, and said that he would try to ensure that they were prosecuted.
Terry Lloyd, Hussein Osman and Fred Nerac were shot near the southern city of Basra two days into the US-led invasion, but none of the US troops involved in the shooting have given evidence.
Walker repeated his complaint at an inquest into the deaths on the same day of two British royal air force personnel who were shot down by a US patriot missile as they approached an air base in Kuwait following a sortie in Iraq.
Britain, which still has about 7,000 troops mainly in southern Iraq, has suffered 121 military fatalities since the start of the conflict.