A company under investigation for a London Olympic Games ticketing scam had been accused of cheating fans out of Rugby World Cup seats.
Police have issued a warning over websites run by the Norwegian company known as Euroteam, which is offering tickets to the London Olympic and Paralympic games.
It is feared New Zealanders who had used Euroteam-linked sites such as www.2012tickets.org or www.londonsummergames.org may never receive their tickets.
Euroteam had previously been accused of deceiving fans into buying fake Rugby World Cup tickets at an inflated price on its site worldcup2011.com.
Irish fan Paul O'Brien told the Herald he had spent $6243 on tickets to the Ireland team's four pool games and two quarterfinal matches at the site.
The tickets never came.
Many other complaints about the company have been posted on the internet, and a blog catalogues warnings over its alleged scams.
Police believe the company is now turning its attention to the London Olympics.
London Detective Superintendent Nick Downing said New Zealanders who had made purchases from Euroteam were in danger of not making it into the games.
"I am seriously concerned that anyone who has bought Olympic or Paralympic tickets will now not receive them."
"There is an ongoing investigation by the Norwegian Police into the wider activity of this company, and we know that the company have stated that they have not sourced all of the Olympic and Paralympic tickets that they have sold."
Anyone who had bought tickets from Euroteam should attempt to contact the company directly and seek advice from the point of payment provider, police said.
Sites under suspicion: