Cape Town - Former All Blacks and Cats Super Rugby coach, Laurie Mains, has slammed South Africa's emphasis on quotas in rugby, saying that the Springboks' best days are behind them.

In an interview with foxsports.com.au, Mains did not hold back.

Mains believes that the Springboks' days of being top competitors on the international stage are over and that the quota system is the main reason why.

New Bok coach Allister Coetzee has been told that half of his squad must be made up of players of colour by the 2019 World Cup.

Mains, the All Blacks coach at the 1995 Rugby World Cup, was in charge of the Cats in Super Rugby for two years in 2000 and 2001.

"When I coached over there I could see the reason for it (a quota system)," Mains said.

"It was a genuine attempt to create opportunities for the black and coloured players and I respected that, because there hadn’t been big numbers of them.

"But heavens above, that’s 15 years ago."

Mains believes that the current Bok side should be picked on merit alone and that, in his mind, all players in South Africa have had an equal chance to develop over the past 15-18 years.

Mains' prediction for the future of the Springboks was equally hard-hitting.

"For my money they’re gone, with racially selecting teams, they’re not going to cut it," Mains said.

"With the quota system they have, I think the days of them being top competitors are over."

The Springboks are next in action when the Rugby Championship begins on August 20.