Help-to-Buy 'not for second homes'
There had been concerns that second-home buyers would be able to access the scheme, which was designed to help first-time buyers on to the property ladder.
But at Prime Minister's Questions on Wednesday, Mr Cameron ruled it out.
His comments came after a question from Labour MP Seema Malhotra.
She said: "Last week you couldn't confirm that taxpayers would not subsidise foreign buyers of property in the UK.
"Perhaps you could instead clarify whether your Help-to-Buy scheme will see taxpayers help fund purchases of second homes and holiday cottages?"
Mr Cameron replied: "First of all, this scheme is for people's only home. It will have a mechanism in place to make sure that is the case.
"The second thing, which is important, is in order to take part in this scheme you have to have a credit record and you have to have a credit record in this country so no, it won't do what you say it would."