British Defence Secretary Liam Fox said on Thursday those forecasting the demise of the ruling coalition after local elections next week underestimated its determination to deal with a record budget deficit.
Local elections and a referendum on electoral reform next Thursday are expected to strain the Conservative-led alliance, formed a year ago.
"The point is that the coalition needs to exist, because there is a national economic emergency, and whatever happens on polling day next week, that deficit, and that economic emergency will still be there, and we will still need the coalition to continue to enable us to deal with that problem," Fox said.
Fox is a Conservative minister in the alliance with the smaller, centre-left Liberal Democrats.
Support for the Lib Dems has plummeted since they joined the Conservatives in a cost-cutting government and reneged on a pledge to cut university fees, leading to speculation the alliance could weaken or even split.
"Before anyone writes premature obituaries for the coalition government, you need to understand how much we believe in the need for the coalition to exist, to continue and to succeed," he said at a lunch with journalists in parliament.
Any sign the coalition was weakening would alarm financial markets, which have so far backed the government's plan rapidly to eliminate a deficit that was running at 10 percent of national output last year.
The coalition is expected to hold together because of the fear of defeat in any snap general election.
The opposition Labour party is ahead on 42 percent in national polls, while public backing for the Lib Dems has more than halved to 10 percent since last May's general election, with the Conservative vote steady at around 36 percent.
In the run-up to the polls Lib Dem ministers have fired increasingly bad-tempered barbs at their Conservative partners over their negative campaigning in a referendum also being held next week on reform of voting in parliamentary elections.
Two opinion polls on Thursday showed opposition rising to a switch from the current first-past-the-post system to the alternative vote (AV), a change the Conservatives oppose and the Lib Dems support.
The referendum was the key to the Lib Dems joining the coalition. They want a voting system more favourable to smaller parties after years of being squeezed by the larger Conservative and Labour parties.
Losing the referendum will put pressure on Deputy Prime Minister Nick Clegg, the Lib Dem leader, to justify his party's continuing alliance with the Conservatives and could even spark a challenge to his leadership.