David Cameron is refusing to revert to a 'plan B' despite the double-dip recession and a new polling setback for his party.
A Sunday Times poll by YouGov has put the Conservatives on just 29%, their lowest level of support since 2004, after figures confirmed Britain was back in recession last week.
Labour is on 40% and the Liberal Democrats on 11%, with Ukip standing at ten per cent.
"It has been a difficult month," Mr Cameron conceded.
"But it's far more difficult for people trying to find work... what I have to do is convince people we're taking the right long-term decisions to deal with problems in our country that have existed for many years."
"We've got to strain every sinew to make sure we get our economy growing."
The UK is back in recession after figures from the Office for National Statistics showed a 0.2% contraction in the first three months of 2012, following the 0.3% negative growth seen in the final quarter of 2011.
That has triggered question-marks about the coalition government's economic policy of drastic spending cuts to eliminate the country's public spending deficit entirely.
Shadow chancellor Ed Balls is challenging George Osborne to a TV debate about the state of the economy.
"The government said we have got a plan, it will work, we will secure recovery, we will get unemployment down, we will get the deficit under control and on every one of those measures it has failed," Mr Balls told the Observer newspaper.
"In politics and especially in economics and politics, when things start to go wrong, the sooner you admit it the better.
"The thing that frustrates me is that for a year is how arrogantly George Osborne has said, 'No my plan will work – you are wrong', and we are a year on and it is now too late."
Mr Cameron insisted in an interview with BBC1's The Andrew Marr Show that the government would not change course, however.
"The figures this week were extremely disappointing... but I tell you what we absolutely mustn't do and that is throw away our plans for dealing with the debt, dealing with the deficit," he added.
"Because if we did that we'd lose the low interest rates we have, [which are] absolutely vital for recovery."
Mr Balls wants to "talk this through" with the government to underline the "big choices" Britain faces as ministers work out "how we get out of this very deep hole".
"The economy continues to underperform and, Japanese-style, it grows below trend and therefore unemployment stays high," he added.
"That sort of stagnation is consistent with a bit of growth, but not enough, that could go on for a very long time.
"I don't see what it is which gets an economy out of [trouble] now when you have got such a fiscal clampdown."
Mr Cameron said private sector growth was the key to recovery, although he conceded that it was not taking place "as fast as I'd like".
He said in areas like exports, employment regulations, manufacturing and infrastructure spending progress was being made, however.
"What's happening in our economy is a very painstaking process of rebalancing," the prime minister said.