Alistair Darling has said Labour should be "proud" of the way it has handled the economic crisis and urged it to take its "good story" to the country.
The chancellor told Labour conference delegates Gordon Brown's leadership had prevented a global recession from turning into a depression.
He also promised new laws within weeks to crack down on bank bonuses driven by "greed and recklessness".
He said the Tories' approach to the economy was "downright dangerous".
Labour is hoping its autumn conference, the last before a general election, will help it to fight back against the Tories.
Mr Darling said the party had a lot to "be proud" of its handling of what he said was "an unprecedented" economic crisis.
Addressing bank bonuses, he said he would bring in new laws within weeks to ensure that rewards were not paid automatically but were tied to long-term performance.
We must keep the public finances on a sustainable path because the long-term health of our economy depends on it
Chancellor Alistair Darling
"Let me assure the country - and warn the banks - that there will be no return to the business as usual for them. So in the next few weeks we will introduce legislation to end the reckless culture that puts short-term profits over long-term success," he said.
The "greed and recklessness" shown by banks over the past two years must never again be allowed to "endanger the whole global economy and the lives of millions of people", he added.
The BBC's deputy political editor James Landale said Mr Darling had turned up the heat on the issue confident that his message would be popular in the country.
But he also said ministers were worried about the public backlash should there be a return to huge bonuses at the end of this year.
Mr Darling said it was "too early" to say that the economic recovery was underway and stressed that it was vital that Labour continued to support investment.
"We can't sit back and relax. There are many business and families struggling to keep their heads above water."
Mr Darling said he welcomed a "mature debate" on the need for measures to reduce debt levels and said public spending would have to be "tighter" in the years ahead.
He said new legislation would require the government to demonstrate how the deficit was being reduced every year, repeating earlier calls from Mr Brown for the need to cut costs, waste and spending in low priority areas.
MONDAY'S CONFERENCE HIGHLIGHTS
09:30: Speech by Scottish Secretary Jim Murphy
09:50: Welfare and economy debate
12:00: Speech by Chancellor Alistair Darling
14:15: Speech by Business Secretary Lord Mandelson
15:20: Debate on the environment, energy and transport
17:00: Debate on the 2012 Olympics
"We must keep the public finances on a sustainable path because the long-term health of our economy depends on it."
But he said the Tories had "failed every test" over the economy over the past two years and would pursue an ideologically-driven approach to cutting spending which he described as "wrong, naive and downright dangerous".
He added: "Within months, the country faces a big choice. A choice not just about who's in government but about values that will shape our country and the opportunities for our people. A choice that will affect every area of our lives, every aspect of our future."
In a newspaper interview before the conference began, Mr Darling warned the party that it had "lost the will to live" and must raise its game if it was to have any chance of winning the election.
Cabinet ministers have been lining up to urge the party to fight for victory while Mr Brown told delegates on Sunday that "we will not win every seat in the general election - but we will win many that people think we will not win".
Shadow Chief Secretary to the Treasury Philip Hammond said: "If the test of a speech at this Labour conference is whether it contains any new ideas, then the Chancellor just failed.
"Today Alistair Darling talked of tough decisions, and then took none - delivering instead a speech that was entirely negative, filled with misleading claims about Conservative policies and devoid of any vision for the future."
The first day of conference saw a row about Mr Brown's appearance on BBC One's Andrew Marr programme, where he was asked about his health.
In the exchanges, Mr Marr asked about Westminster rumours he might use concerns about his health as a reason for stepping down as prime minister ahead of a general election.
He told Mr Brown he wanted to ask about "something everybody has been talking about in the Westminster village... A lot of people in this country use prescription painkillers and pills to help them get through. Are you one of them?"
The prime minister replied: "No. I think this is the sort of questioning which is all too often entering the lexicon of British politics."
And he denied his sight was deteriorating - something he was asked about last week on US television.
Mr Brown lost the sight in one eye in a rugby accident as a teenager and suffers reduced vision in the other eye, but he said he had recently undergone an annual check-up which showed no deterioration in the vision of his good eye.
When Andrew Marr asked again about the issue of painkiller use, Mr Brown said: "I've already answered that question."
Lord Mandelson later criticised the "degree of personal intrusiveness" in the interview and said he did not have "the foggiest idea" what Andrew Marr had been talking about.
Alastair Campbell, Labour's former director of communications and strategy, told BBC Radio 5 live: "I think people were genuinely really quite shocked that Andrew Marr, on a mainstream BBC programme, sees it as his job now to float rumours that are flying round the internet."
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