"There was a fire this evening at approximately 7.30pm in the outdoor area of Kiwi House in London, an outdoor oven caught fire," the New Zealand Olympic committee said in a statement.
"People were safely and swiftly evacuated, and emergency services were called. Once people were safely evacuated the BBQ gas bottle exploded. There are no reported injuries and the situation is now contained."
BBC television reported that up to 700 people were evacuated after the fire near King's Cross station. Two fire engines and 10 firefighters put the blaze out.
Kiwi House, inside Central St Martins College, is open to athletes, officials and the public and is a short walk from the Javelin high speed train terminal that takes passengers to the Olympic Park.