Rupert Murdoch's British tabloid The Sun published nude photographs of Prince Harry on Friday, claiming it defied royal orders not to print them in defence of press freedom.

A grainy image of the 27-year-old prince, cavorting naked with a female friend in a Las Vegas hotel suite, appeared on the front page with the headline, "Heir it is!"

British newspapers had on Thursday obeyed the royal family's request not to print the pictures of the third in line to the throne, which first surfaced Wednesday on the US gossip website TMZ before spreading virally online.

But The Sun broke ranks on Friday, saying it was 'ludicrous' that British newspapers were not allowed to print photographs which had already been seen by millions on the Internet and in foreign newspapers.

The Sun's managing editor David Dinsmore said the tabloid -- Britain's biggest-selling newspaper -- had 'thought long and hard' before publishing the pictures of Harry.

"This is about the ludicrous situation where a picture can be seen by hundreds of millions of people around the world on the Internet, but can't be seen in the nation's favourite paper read by eight million people every day," Dinsmore said.

"We're also big fans of Prince Harry. He does a huge amount of work for this country and for the military and for the image of both of those institutions," he added.

"We are not against him letting his hair down once in a while. For us this is about the freedom of the press."

Royal officials had argued that printing the pictures would breach Harry's privacy, and they contacted Britain's Press Complaints Commission (PCC) watchdog to request that newspapers not publish them.

A spokeswoman for Harry's residence, Clarence House, declined to say on Friday whether the palace would take legal action against The Sun.

"We have made our views on Prince Harry's privacy known," she said.

"Newspapers regulate themselves, so the publication of the photographs is ultimately a decision for editors to make."

Industry figures say the wider British media complied with the request due to fears that the phone-hacking scandal at Murdoch's new-defunct News of the World will spark tougher regulation of the press.

The scandal, which saw Murdoch close the 168-year-old tabloid in July last year, sparked an inquiry led by judge Brian Leveson, who is due to make recommendations on the future of press regulation by the end of the year.

"Most of the tabloid papers, post the Leveson Inquiry and all the revelations about the News of the World, are effectively running scared," said Gary Horne, Journalism Course Director at London College of Communication.

"They're trying not to do anything to antagonise Leveson while he's drawing up his report," he told AFP.

The media have also raised questions about why Prince Harry's protection officers allowed him to be photographed naked in the hotel suite by revellers he had just met, reportedly during a game of "strip billiards".

Officers from London's Metropolitan Police, who usually accompany the royal family in public, have previously been known to intervene when people have attempted to photograph the royals in bars or nightclubs.

But TMZ claimed that one of Harry's minders 'lackadaisically' told women who were snapping the nude prince on their camera phones: "Awww, come on... no photos."

The website has warned that more nude photos may yet emerge as 'several girls' had taken pictures at the wild party in Las Vegas.

Harry is a trained army helicopter pilot who has served in Afghanistan and has said he wants to return to serve there.