The South African Rugby Football Union's executive have issued the warning because teams selected for the inter-provincial tournament remain predominantly white.
The controversy came to a head during the opening round of the competition last weekend when most of the 12 provinces in action selected all-white sides, discarding black players who had appeared in the Vodacom Cup earlier in the season.
The Vodacom Cup runs in conjunction with the Super 12 series and has successfully applied quotas for two years. The five "southern" provinces - where there is a long history of black rugby - have to select three black players at all times while the rest field two. But when the Currie Cup sides were announced, black players such as the Gauteng Lions wing Jaco Booysen, joint second in the competition's try-scoring chart, and the centre MacDonald Masina, named as the best defender in the series, were omitted.
Even Western Province, one of the southern provinces, named only one black player in their team, but their neighbours Boland fielded the five black players they had routinely used in the Vodacom Cup.
In a statement, SARFU said: "The 14 provinces have until the end of July to honour a commitment made by their presidents earlier this year that opportunities be provided for players of colour in the Currie Cup. The SARFU executive committee decided that if provinces did not show their commitment to transformation over the next two months, it would have no option but to implement quotas."
The 25-year-old Scottish lock Richard Metcalfe, who is 7ft tall and weighs more than 20st, has signed a new three-year contract which will keep him with Northampton until 2002.
New Zealand have named an unchanged squad for their Test match against Western Samoa in Auckland on Friday.
The 24-strong squad, which contains eight uncapped players, was actually picked two weeks ago but the All Blacks' selectors were forced to draft in the Canterbury captain Todd Blackadder and the Auckland back Carlos Spencer for last week's 22-11 victory over New Zealand A because of injuries.
Blackadder and Spencer have returned to the A squad, but the selectors have kept faith with the Otago No 8 Taine Randell as captain, even though he led New Zealand to an unprecedented five successive Test defeats last year.
New Zealand squad: Backs: P Alatini, T Brown, C Cullen, D Gibson, A Ieremia, B Kelleher, J Lomu, J Marshall, A Mehrtens, T Umaga, J Wilson. Forwards: A Blowers, R Brooke, G Feek, M Hammett, C Hoeft, I Jones, J Kronfeld, N Maxwell, K Meeuws, A Oliver, D Mika, T Randell (capt), K Vanisi.Reuse content