The chancellor has said he is “sorry” for not helping “everyone in exactly the way they would have wanted”.
Rishi Sunak said the government was “throwing everything we can” to stem job losses with the plans unveiled on Wednesday.
But he will not be able to protect “every single job” as the UK enters a “severe recession”.
He admitted some of the bonuses to take back furloughed staff would go to firms that were already keeping workers on.
The UK is “borrowing record amounts”, he said, but “it is the right thing”.
It comes as figures released by the Treasury reveal that public spending on the battle against coronavirus has risen to nearly £190bn.
Mr Sunak told BBC Breakfast: “If you’re asking me ‘can I protect every single job’ of course the answer is no.
“‘Is unemployment going to rise, are people going to lose their jobs?’ Yes, and the scale of this is significant.
“We are entering one of the most severe recessions this country has ever seen. That is of course going to have a significant impact on unemployment and on job losses.”
He added: “Have we been able to help everyone in exactly the way they would have wanted? I’m sure not. And I’ve said previously we haven’t been able to do that and for that I’m sorry.”
The chancellor announced a series of measures to help the economy on Wednesday, including a VAT cut for the hospitality and tourism sectors, a bonus scheme for employers and an eating out money off scheme for August.
Mr Sunak said the £1,000 bonus being offered to businesses that keep furloughed staff in jobs until January would be a “dead weight” cost, as some employers who intend to retain workers anyway would benefit.
The Chancellor told BBC Radio 4’s Today programme: “Throughout this crisis I’ve had decisions to make and whether to act in a broad way at scale and at speed or to act in a more targeted and nuanced way.
“In an ideal world, you’re absolutely right, you would minimise that dead weight and do everything in incredibly targeted fashion.
“The problem is the severity of what was happening to our economy, the scale of what was happening, and indeed the speed that it was happening at demanded a different response.”
He said that “without question there will be dead weight – and there has been dead weight in all of the interventions we have put in place”.