The International Cricket Council's (ICC) investigation of three Black Caps is reportedly centered on the trio's activities when they played together in Indian Twenty20 competition in 2008
According to Stuff.co.nz, the investigations relate to matches played three to four years ago and involved alleged offences in more than one country.
Chris Cairns, Lou Vincent and Daryl Tuffey played together for the Chandigarh Lions in India in 2008 in the now-defunct Indian Cricket league (ICL) that was set up to counter the Indian Premier League as the T20 game exploded in popularity, the report added.
Meanwhile, Vincent said on Thursday that he was co-operating with the ICC's anti-corruption unit.
Former NZC all rounder Cairns said he was "100 percent in the dark" about the allegations, but affirmed that the ICC investigation should run its course.
However, the ICC does not have the jurisdiction to adjudicate on non-sanctioned "rebel" leagues, which means their investigation of the former Black Caps must come from subsequent events.