The rules around how doctors store vaccines have been strengthened after incorrectly stored shots sparked fears thousands of patients would need to be re-vaccinated.

It comes after a government audit of general practitioners showed some were not monitoring vaccine storage according to national guidelines.

The audit came after it was revealed in June that some vaccines administered since 2010 by Drs Darrel and Brinda Weinman at their Burwood practice may not have been effective, with some shots found to have been incorrectly stored or out of date.

NSW Health on Thursday asked all GPs to ensure at least one of their staff members has training in cold-chain storage after completing an online training module.

Random audits will be conducted to check GPs are complying with the new requirement.

"Vaccines need to be stored at an optimal temperature range to ensure patients are protected from illness such as the flu, measles or meningococcal disease," chair of the Royal Australian College of General Practitioners NSW/ACT Dr Charlotte Hespe said in a statement.