David Cameron said it was "absolutely" his intention to keep the coalition together until the 2015 general election.
The Prime Minister told BBC Radio 4's Today programme there are some big and bold reforms ahead and dismissed suggestions the government was running out of steam.
On working with Nick Clegg until the next general election, he said: "That is absolutely my intention and has always been. This is a Government that has an enormous programme of work."
"To anyone who doubts the life there is left in the coalition, I would argue there is more to come. Very bold reforming and strong government, and that is what we will be right up till polling day," he added.
The Prime Minister told Total Politics magazine that the coalition was the best way to get things done but "if that wasn't the case then we'd have to face the new circumstances in whatever way we should."
The Deputy Prime Minister will say: "He echoed exactly what both of us have always believed: this coalition has been remarkably radical; it still has work to do; and the best way for us to serve and improve Britain is by finishing what we started.
"I am absolutely committed to this coalition lasting until 2015 - as is the Prime Minister."
Claims that it was in either or both parties' interests to "prematurely pull the plug" were wrong, he will suggest.