David Cameron has insisted the Spending Review cuts were conducted in the right and "fair" way, with the highest earners bearing the greatest burden.
In a No 10 podcast, the prime minister said the UK faced a "hard road" but he did not "underestimate how difficult this will be".
He said drastic action was essential to cut the economic deficit.
The Institute for Fiscal Studies has suggested the burden of cuts would fall disproportionately on the poorest.
The spending cuts aim to reduce the economic deficit by £81bn over four years.
In the No 10 podcast, the prime minister said: "We didn't just do the right thing, we did it the right way. We've gone about these spending cuts in a way that is fair and in a way that promotes economic growth and new jobs.
"Fair because if you look at the figures, you'll see the highest earners aren't just paying more in cash, they are paying more as a percentage of their income.
"As we promised, those with broader shoulders are bearing a greater burden.
"What's more we've chosen to protect the services that families rely on, like the health service, schools, and social care."
But analysis by the Institute for Fiscal Studies suggests many of the cuts will fall on the nation's poorest. The richest 2% will be subject to tax rises announced under Labour.
In his podcast, Mr Cameron said that the spending review had also been designed promote economic growth.
"We're going to make the next decade the most entrepreneurial in Britain's history, and transform the fortunes of our country," he said.
"I know the road ahead will be hard. But we have a plan. We are seeing it through. And believe me, the destination will be worth it. A Britain with a strong, positive and confident future."