Super Rugby expanded to 18 teams, including sides in Japan and Argentina, this past season but critics in New Zealand felt playing schedules were unfair and that the post-season format was not an accurate reflection of the competition.
Earlier this week, Andy Marinos, the head of tournament organisers SANZAAR, told reporters in Sydney there would be no change to the competition format next season.
NZR's Tew, however, said that he had lobbied to change the finals format, where each of the four conference winners – one each in New Zealand and Australia and two from South Africa – are given home advantage throughout the post-season.
"We couldn't get agreement from Australia and South Africa," Tew told a conference call with New Zealand media on Friday. "We've tried and haven't completely given up but it's unlikely we'll get any substantial change in the finals format next year.
"If there are any changes for 2018, then that gives another chance to have that debate.
"We think it makes much more sense to have a straight top eight. It makes it a lot easier for the fans. They can almost disregard the complications of the conferences and just look at the log and say 'is my team in the top eight'."