Earlier, Melbourne City said they had been told there's no prospect of delaying or rescheduling despite a 37-degree forecast for the capital on Sunday.
In a statement released this afternoon, the FFA said, "The FFA Heat policy is based on the forecasted Wet Bulb Globe Temperature (WBGT) and a threshold of 28 degrees is used to consider delay or postponement. There is a high probability that the WBGT of 28 degrees could be exceeded on Sunday at the scheduled kick off time of 2:00pm (AEDT).
Last weekend, A-League players from Adelaide United's match against Wellington Phoenix suffered heatstroke after playing in similar conditions.
A-League chiefs dismissed the suggestion it didn't take player welfare seriously, implementing drinks breaks despite not reaching a temperature threshold to do so.