The Prime Minister says it would be outrageous and unfair if all New Zealand sportspeople were tarnished by match-fixing allegations surrounding a former Black Cap.
Britain's Daily Mail newspaper reported that the former New Zealand international, Lou Vincent, told investigators he was offered sex and cash to fix cricket matches.
The International Cricket Council's anti-corruption unit is investigating games involving the Auckland Aces from the 2012 Champions League tournament in South Africa after allegations of spot-fixing.
Mr Key said that, for the most part, he was confident New Zealand sportspeople played fairly and within the rules.
Mr Key said it was important that the ICC's investigation was completed quickly.
A former England international cricketer revealed he was approached by former Black Caps player Lou Vincent to match fix.
Mal Loye, who used to open the batting with Vincent at English county side Lancashire, and played for the England one day side, told the Daily Telegraph newspaper that in 2008 Vincent asked to help him organise spot-fixes.
Loye said he ignored Vincent's requests and only came forward with his story when approached by England and Wales Cricket Board investigators last year who were piecing together the case against Vincent.
And the Daily Mail said it hadseen documents from the International Cricket Council's investigation into Vincent.
The paper said Vincent told investigators he was offered a woman and cash to fix matches with Vincent apparently identifying 12 games around the world where he was involved in match fixing between 2008 and 2012.
It said Vincent was also threatened by a well know international player after a fix failed to come off.
The paper said Vincent maintained he was still owed over $200,000 for helping to match fix in the rebel Indian Cricket League.