United States president Barack Obama has struck back at conspiracy theorists questioning whether he was born in America, branding it a silly distraction.

After years of speculation about where he was born Mr Obama has unexpectedly made his detailed birth certificate public.

The move is an attempt to end a long-standing debate within Republican circles that he was not born in the United States and is therefore an illegitimate president.

The so-called birther issue has come to prominence again recently, with billionaire Donald Trump raising it as he campaigns for the Republican nomination for next year's presidential election.

It is unclear whether the certificate will satisfy the most hardcore conspiracy theorists, who claim Mr Obama might have been born in Kenya or Indonesia.

Previously, the 2008 Obama presidential campaign had released a short-form computerised abstract of the kind issued to any Hawaiian when they ask for a copy of their birth certificate.

The new document confirms what a shorter version has said - that Mr Obama was born in Hawaii on August 4, 1961.

It lists his parents as Stanley Ann Dunham, 18, from Wichita, Kansas and Barack Hussein Obama, 25, from Kenya.

It provides a little more information, such as that he was born at Kapiolani Maternity and Gynaecological Hospital.

The document was obtained by Mr Obama's personal lawyer, who travelled to Hawaii to retrieve a copy and returned with it on Tuesday.

In an extraordinary live television appearance, Mr Obama said it was time to end the silliness.

"I'm speaking to the vast majority of the American people, as well as to the press," he said, branding the row as a distraction from serious issues.

"We do not have time for this kind of silliness. We've got better stuff to do. I've got better stuff to do."

Television networks broke into regular programming to cover the statement live.

The US Constitution specifies that presidents and vice-presidents must be American born, and not simply US citizens, and conservative pundits have fanned the controversy to raise questions about Mr Obama's political legitimacy.

The controversy has morphed from the right-wing political fringe into the centre of the US political debate: a recent CBS/New York Times poll found a quarter of Americans incorrectly thought Mr Obama was not US-born.

But the president, who confessed he was bemused and puzzled by the controversy, said America faced "monumental" choices on reviving the economy and hot-button issues like rising petrol prices squeezing consumers.

"We're not going to be able to do it if we are distracted. We're not going to be able to do it if we spend time vilifying each other," he said, in an apparent attempt to elevate America's bruising political debate.

"We're not going to be able to do it if we just make stuff up and pretend that facts are not facts.

"We're not going to be able to solve our problems if we get distracted by sideshows and carnival barkers. We live in a serious time right now."

Mr Trump claimed victory after the release of the birth certificate.

"I've accomplished something that nobody else has been able to accomplish," he said.

"I was just informed while on the helicopter that our president has finally released a birth certificate. I want a look at it, but I hope it's true.

"I am really honoured frankly to have played such a big role in getting rid of this issue.

"We have to see is it real, is it proper, what's on it. But I hope it checks out beautifully. I am really proud."

Republicans, despite the fact that sections of their membership have been challenging Mr Obama on the issue, said that the president had been wrong to raise it to the level of a presidential statement.

"As I've repeatedly stated, this issue is a distraction," said Reince Priebus, the chairman of the Republican National Committee.

"The president ought to spend his time getting serious about repairing our economy, working with Republicans and focusing on the long-term sustainability of Medicare, Medicaid, and Social Security.

"Unfortunately his campaign politics and talk about birth certificates is distracting him from our number one priority - our economy."

- ABC/AFP