Japan are set to join an Argentina franchise and South African side the Southern Kings in making it an 18-team competition.

News Corp newspapers are reporting that contingency plans have been drawn up that involve running a 17-team format without Japan, or going to 16 teams with just the Argentinean side, which is progressing well in terms of recruitment and organisation. Another possibility raised was bringing in a late replacement for Japan to keep the 18-team structure.

The Japanese scenario unfolds as national coach, former Wallabies mentor Eddie Jones, confirmed he would be stepping away from the scene over there.

He had been indicated as a possible coach of the Super Rugby side, but now seems destined to take charge of the Stormers franchise in Cape Town.

"The [Japan Rugby Football] Union are going to announce this afternoon that I will not be continuing after 2015," Japanese news agency Kyodo quoted him as saying.

"That was always the case as my contract was until the end of the year, so all they are doing is stating the obvious.

"People assumed that as I had been named the director of the new Super Rugby side I would stay on. But that was just an administrative role not a coaching role. All I was doing was help get it set up."

Officials from Sanzar toured Japan earlier this month and raised concerns that suggested a delay in the Asian stronghold's entry could be a possibility.

It seems a power struggle between the wealthy company-based Japanese clubs and the Super Rugby ambitions are at the base of Japans problems.

Stuff.co.nz