Foreign Secretary William Hague flew into Kabul today ahead of talks with political and military leaders in the Afghan capital.
He was heading a senior ministerial delegation also consisting of Defence Secretary Liam Fox and International Development Secretary Andrew Mitchell.
The visit is the first by members of the new coalition Government and reflects the high priority being given by it to the conflict.
It came as the death of another British serviceman was confirmed yesterday, the 286th in the campaign and the first fatality since the Conservative-Liberal Democrat coalition took office.
The trio of ministers, all Tories, are to conduct a series of meetings today with senior Afghan politicians including President Hamid Karzai.
They will also be meeting the US commander of the international forces in Afghanistan, General Stanley McChrystal, and other military top brass.
Speaking on their RAF flight into Kabul in the early hours of this morning, the ministers indicated they were not planning any significant breaks in UK policy on Afghanistan.
Mr Hague said there had been "some important changes" in strategy recently, pointing to President Barack Obama's intervention last year as well as the London Conference chaired by then prime minister Gordon Brown.
"We want to give that strategy the time and support to succeed," he said.
He said the three ministers were travelling and working together to make sure they had "a properly coherent British approach to Afghanistan".
"We are taking stock as a new government, we want to see how things are working, we want to hear the military advice, we want to talk to the Afghan government themselves, we want to discuss the detail with the United States."
Mr Hague added: "The question is how to support the efforts of the Afghan government and our Nato partners, not whether to support them."
Mr Fox insisted the sacrifices of British troops remained essential.
"When I got this job the very first question I asked myself was 'do we have to be in Afghanistan, do our troops have to take these costs of life and limb?'
"And my answer is still 'yes'."
He added: "We cannot allow Afghanistan once again to become a failed state and a launching pad for international terrorist groups."
He said the Labour government had acted "too late" on the provision of resources and so was "always playing catch-up".
"I have got a chance to ask those on the ground if they think they have got all they need to do the job," he said.
In an interview with The Times, he said, "I want to talk to people on the ground, our trainers, to see whether there is room to accelerate it without diminishing the quality."
There must be a distinction between military and humanitarian goals, he went on.
"We are not in Afghanistan for the sake of the education policy in a broken 13th-century country. We are there so the people of Britain and our global interests are not threatened."
Mr Mitchell said work to create a functioning state in Afghanistan was "absolutely crucial".
"We need to ensure that we help the Afghan people to build a functioning state," he said.
"That's about providing basic education and healthcare facilities, but it's also about ensuring there are opportunities for promoting livelihoods so that people have jobs."
There were also issues around systems of governance and justice that had to be addressed, he said.
He insisted that "progress is being made", but added: "If we are going to prioritise making sure there is a functioning state in Afghanistan, then development, the work we are doing in that respect, is absolutely crucial."