Theresa May has accused peers of trying to “undermine” press freedom by calling for a second Leveson-style inquiry.
The Prime Minister hit out at members of the House of Lords after they voted to launch a fresh probe into media ethics.
She vowed to overturn their decision to push for tighter regulation of the press.
The vote by peers comes after the Mirror has exposed a series of expenses scandals in the Lords.
Our front page scoops including the revelation in September last year that Lords who didn’t take part in any debates for a year claimed £1.2million expenses.
Tory MP Jacob Rees-Mogg suggested their vote for a second phase of the Leveson inquiry succeeded because of peers “who wish to keep their dirty linen in the closet”.
MPs will vote on the amendment in the Commons in the coming weeks.
Peers inflicted a double defeat on the Government’s Data Protection Bill on Wednesday.
It passed two amendments to tackle alleged media abuses and backing the launch of the second phase of the Leveson inquiry into press standards.
But Culture Secretary Matt Hancock said the proposed changes would be a “hammer blow” to the local and national press.
Quizzed about the Lords vote after a speech in London, Mrs May said: “I think that the impact of this vote would undermine high-quality journalism and a free press.
“I think it would particularly have a negative impact on local newspapers, which are an important underpinning of our democracy.
“I believe passionately in a free press. We want to have a free press that is able to hold politicians and others to account and we will certainly be looking to overturn this vote in the House of Commons.”
Following a lengthy and impassioned debate on Wednesday, the House of Lords voted for an investigation to be held into alleged data protection breaches by the media.
Supporters of the move argued it was needed amid claims of ongoing press abuses.
But opponents said it amounted to “harassment” of the media.
The unelected chamber also backed a controversial measure which would see newspapers not signed up to a state-supported regulator pay their own and their opponent’s legal costs in relation to alleged data protection breaches, even if they were successful in court.
The Government argued the amendments were not appropriate given the head of the original independent inquiry, Sir Brian Leveson, was reviewing responses to the Government’s consultation on a second inquiry into the conduct of the British press.
The call for a public inquiry into data protection breaches by national newspapers was tabled by independent crossbencher Baroness Hollins, whose family was the victim of press intrusion after her daughter Abigail Witchalls was stabbed and left paralysed in 2005.
Criticising the Government consultation, she argued it should be “simply a matter of good faith that an inquiry promised to victims of crime should be completed”.
But Mr Hancock warned: “This vote will undermine high-quality journalism, fail to resolve challenges the media face and is a hammer blow to local press.”
The Society of Editors welcomed assurances that the Government will seek to overturn the Lords votes.
Executive director Ian Murray said it was “very worrying” that peers have voted for measures that the Society believes would undermine the media and backed an inquiry similar to Leveson but shorn of any requirement also to probe the actions of police or politicians.
“Even if we put to one side the obvious party political games being played here, for so many of those who have a hand in deciding how our country is safeguarded to believe the best way forward is to threaten to bankrupt newspapers if they carry out investigative journalism is appalling,” said Mr Murray.
“Here we are, the home of free speech and freedom of expression, and in our Mother of Parliaments we have peers with a full understanding of what they are doing voting effectively to put an end to investigative journalism, bully publishers into coming under state control and probably close down local newspapers for good.
“And all this against a backdrop of voting to exempt themselves and the police from the inquiry into the media they feel is still so essential. The sheer hypocrisy of it beggars belief.”
The Society warned that under the Lords amendments, publishers could only avoid the requirement to pay all costs if they signed up to Government-backed regulator Impress, which is funded by tycoon Max Mosley.
The vast majority of newspapers, both national and local, belong instead to the Independent Press Standards Organisation (Ipso).