Norway's football federation is planning to review all international transfers over the past four years for possible fraud and tax violations.
The federation said in a statement Wednesday it would hire an outside auditor to carry out the review, which would look into transfer contracts with players from the top two men's football leagues and the top women's league.
The decision follows several cases of alleged fraud involving teams from Norway's top league.
Last week Estonian defender Raio Piiroja and three officials from Fredrikstad were charged with tax fraud in connection to the player's contract.
Piiroja, who was transferred to Dutch club Vitesse last summer, was in Norway this week to speak with investigators.
Police suspect that Piiroja concealed income from tax authorities, helped by his agent, Fredrikstad and the Estonian club Flora Tallinn.
Piiroja denied any wrongdoing.
Earlier this year two officials from Stabaek and Vaalerenga were arrested following an investigation into fraud centering on Icelandic striker Veigar Pall Gunnarson's transfer between the two clubs.
Police have claimed the clubs structured the deal to lower the French club Nancy's share of the transfer fee.
