They are exploring a "new direction because they felt that the Super 14 competition had reached its use-by date", said The Dominion Post.
The newspaper reports that those unions want to replace Super 14 with a trans-Tasman home-and-away competition involving nine New Zealand teams and five from Australia and excluding South Africa altogether. This would mean doing away with New Zealand's premier domestic competition, the Air New Zealand Cup, according to the report.
The eight unions also want a European-style tournament of 24 teams in four pools of six playing matches every four weeks. It is proposed that this competition would include teams from South Africa, New Zealand, Australia, Japan, the Pacific Islands and America.
Sanzar's Super 14 and Tri-Nations contract with News Limited does not end until 2011, but the report said that this date would have to be brought forward in order to have the new competitions up and running in 2010.
However, the New Zealand Rugby Union (NZRU) has stated it will not back such a position, with general manager Neil Sorenson suggesting that such a restructure would be at odds with the way the union wishes to develop the game.
"Sanzar's current position is that it is a very much a three-country expansion of Super rugby with South Africa involved," said Sorenson.
"The trans-Tasman idea does not include South Africa and that is absolutely not the NZRU's preferred position at the moment," he is quoted as saying in The Dominion Post.
"At this stage, Sanzar are unified in New Zealand, Australia and South African teams being involved in Super rugby and Tri-Nations going forward.
"There can be no breakup of Sanzar, absolutely not. Sanzar needs to remain very, very strong, particularly in today's rugby environment which is very trying."
Sorenson said the NZRU had had a lot of options "thrown at us" from various groups and individuals. "This one has been mooted before . .. we have been over some of these ideas over the last few weeks."
The NZRU had been invited to attend a meeting on Friday but Sorenson was unsure if it was about the reported new competitions.