JOHANNESBURG (Reuters) - South Africa's central bank said that changing its shareholding will not affect its mandate, the regulator said on Wednesday hours after the ruling party proposed at a policy conference to nationalise the bank. "The shareholding of the SARB (South African Reserve Bank) has no bearing on the policy or regulatory role that the SARB plays," the bank said in an emailed statement to Reuters, saying it had noted the resolution by the African National Congress. The bank said that even if its shareholding were to change, it would continue to derive its mandate from the constitution. The party's proposal is likely to raise concerns about the independence of the reserve bank after an anti-graft watchdog recommended its mandate be changed to place more focus on growth and not just inflation and the rand currency. (Reporting by Olivia Kumwenda-Mtambo; Editing by James Macharia)