Gordon Brown has sought to regain the political initiative, telling business chiefs he was taking the "long-term" decisions Britain needs for the future.
Mr Brown promised new welfare obligations
He would not "shirk" over decisions on things like new runways or new nuclear power stations, the PM told the CBI.
A re-think over capital gains tax was hinted at, as were plans to force more jobseekers to accept training places.
The Tories called the measures "short term", while the Lib Dems called it an "incoherent view on Britain's future".
Mr Brown's speech, his first to the audience of business leaders since he became prime minister, followed a series of problems over emergency funding for Northern Rock and the loss of two discs holding personal details of 25 million people.
He told the CBI conference in London that he would not take short-term decisions that would put economic stability at risk at a time when a new global order could bring problems such as the credit crisis.
He said Britain must "leave behind the old policies of yesterday" and make new long-term decisions on planning, energy, the environment and education to become a global leader in the 21st Century.
Investment in transport infrastructure must be stepped up, he said, saying every year up to 2017 would see a £20bn investment in transport.
The £16bn Crossrail project would go ahead and he said the government would not "shirk" the decision on expanding Heathrow, upon which, he said, Britain's prosperity depended.
Decisions on key national infrastructure projects will be handed to a new independent body and "streamlined", and on energy security, he said a decision on building nuclear power stations would be made early in the New Year.
Following concerns about the decision to scrap taper relief on capital gains tax, Mr Brown said he would continue to "listen and discuss" the issue with businesses.
And he promised tougher rules on people on benefits accepting training offers.
"If the best welfare is no longer the benefits you have today but the skills you gain for tomorrow then the inactive should, wherever possible, be preparing and training to get back into work," he said.
But the Conservatives said, after 10 years in power, Labour had made "very little difference" to the number of people claiming benefits.
Shadow work and pensions secretary Chris Grayling told the BBC Mr Brown had made a "series of bits and pieces announcements" adding: "This does not represent the major step change in welfare that we so desperately need in this country.
"Gordon Brown was talking about arguing for the long term this morning, actually what he's done is going for a series of short term announcements that simply grab the headlines."
Meanwhile acting Lib Dem leader Vince Cable said Mr Brown was providing an "incoherent view on Britain's future", saying last week he talked about the need to protect the environment, while he was now talking of airport expansion and a new generation of nuclear power stations.
At the same conference, the two men vying to be Liberal Democrat leader attacked the government's record. Nick Clegg said the government was "letting business down" while Chris Huhne said not a single Treasury team minister had business or markets experience.
"It takes real ministerial talent and determination to engineer the first full-scale banking panic since the Victorian age, and to lose not one, but two discs with bank accounts of seven million families is frankly astonishing," he said.
And Mr Brown's statement that there would be a stronger role for private and voluntary firms in helping people move from benefits to work, was criticised by trade unions.
A spokeswoman for Unison said: "Study after study shows that the private sector does not deliver good value for money and walks away from contracts when the going gets tough."