John Prescott will chair nine cabinet committees and deputise for Tony Blair on seven others, Downing Street has announced.
The news has been released to counter suggestions that the deputy prime minister is no longer worth his £134,000 ministerial salary after losing his department responsibilities.
In the reshuffle earlier this month, the Office of the Deputy Prime Minister was reinvented as the Department for Communities and Local Government, led by Ruth Kelly, but Mr Prescott kept his title and salary.
In a written statement to the House of Commons this morning, Mr Blair insisted his deputy would have a "wide ranging brief" in both domestic and international affairs.
"Like previous holders of the office, the deputy prime minister will act with my full authority in overseeing the delivery of government business, including delivering key pledges in the 2005 manifesto," he said.
However, when Mr Prescott stood up in the Commons today - the first time he has faced fellow MPs since news of his affair with his secretary broke last month - he was heckled and jeered by MPs on the opposition bench.
As he attempted to explain his new role, phrases such as "domestic affairs" prompted howls of laughter from the Conservatives, and in reference to claims that the affair took place in his office with the door ajar, one asked him to "keep the door shut this time".
There were more shrieks of laughter after one MP asked whether Mr Prescott would continue to have a "hands on role" in housing policy, causing the speaker to warn that if the disruption continued, he would have to restrict MPs' questions.
Like a true veteran, however, Mr Prescott ploughed ahead and made clear that his brief would see him work much harder than his Conservative predecessor, Lord Heseltine.
"There were no complaints about him at the time," he insisted, before declaring: "The prime minister has given me an important job to do and I'm getting on with it."
Mr Prescott has long played a key role as go-between for Mr Blair and the chancellor, Gordon Brown, and is likely to continue this in his new position as a "broker" on government policy.
But shadow constitutional affairs secretary Oliver Heald.today questioned whether this was a government role, and not one more suited to Mr Prescott's position as deputy leader of the Labour party - to be paid for as such.
"Isn't it the blunt truth that his principal role now is as political broker, as a sort of marriage guidance broker between No 10 and No 11? Can he assure us that civil servants in his office won't be dragged into this - and shouldn't the Labour party be paying?" he asked.
Mr Prescott rejected all further quips about his value for money however, and in particular hit out at claims that he has kept two official homes and his famous two Jaguar cars.
"I have one house, and one car, ten years old. I suspect that on the opposite benches, most people have got a lot more than that," he said.