UPDATED 4.40pm: Political jaws are dropping over just how little time US billionaire Peter Thiel spent in the country before being granted citizenship.

LISTEN ABOVE: Newstalk ZB's Chief Political Reporter Felix Marwick joins Larry Williams to discuss Peter Thiel

New information released today shows it was just 12 days over four trips.

Prospective citizens are typically required to live in New Zealand for at least eight months of every year for the preceding five years - that's over 1300 days.

Labour Leader Andrew Little said he's stunned at the news.

"He got his citizenship under this exceptional circumstances category, I think the government has to front up and tell us what those exceptional circumstances were."

"12 days in the country sounds far from exceptional, it sounds most peculiar to me."

Cabinet Minister Nathan Guy, who approved the application, says that fact did not stick out when he made his decision.

He's standing by the call he made.

"I backed the decision in 2011, I back the decision now."

Guy said the businessman had made significant investments in several New Zealand companies and donated $1 million to the Christchurch Earthquake Appeal Fund.

"Think back to that," Mr Guy said.

"We were coming through the global financial crisis, we were just starting to rebuild Christchurch, and this individual stepped up and said he wanted to be part of it."

Andrew Little is demanding the Government release more detail on what Mr Thiel has actually done for the country.

"Tell us what the entrepreneurship is in New Zealand, tell us what the donations are in New Zealand, and let's make up our own minds."

Nathan Guy has no answers as to why, if Mr Thiel is the great ambassador he claims, we only found out about him five years after he was granted citizenship.

"I can't answer that. You'd need to ask Peter Thiel. That's something to do with DIA and it's processes."