A light-hearted road trip to see the launch of New Zealand's first Krispy Kreme has gone from sweet to sour for one couple, after a woman was turned away due to being a foreigner.

Hamilton resident Christopher Smith, 30, arrived at the Manukau City store at 2:30am on Wednesday morning only to have his girlfriend turned away by a tired security guard, Stuff reports.

Arriving so early, Mr Smith was able to secure the 75th place in line and received a prize of a free box of doughnuts for his efforts.

However he was shocked when the security guard asked his girlfriend, who wishes not to be named, if she was a New Zealand citizen.

When she said she wasn't, the guard allegedly replied "she has to go, she has to go", according to Stuff.

Mr Smith asked if his girlfriend could wait in the queue and not claim a prize but the guard said no, meaning she had to wait alone in the car for five-and-a-half hours.

Krispy Kreme's head of marketing, Russell Schulman, told Stuff it was unfortunate Mr Smith's girlfriend was turned away but it was simply the rules of the competition.

"Someone who is a little upset at the rules is unfortunately not an incident for us," he said.

"At the time they said 'they told them the rules, they were written down', so I guess we didn't see it as an issue."

The rules being that apparently foreigners weren't allowed on premises, even if they weren't entering for a prize.

Mr Schulman did admit the company does not have the legal right to ask people to leave the premises if they are a foreigner, and perhaps the security guard was "over-zealous".

According to Mr Smith, at least three others were sent away from the launch due to not being New Zealand citizens or residents.

Newshub.