Copies of a confidential draft ruling by the regulator about an advert from the animal welfare charity’s campaign against the badger cull were leaked to The Daily Telegraph and The Times newspapers.
The advert, entitled Vaccinate or Exterminate?, which drew 119 complaints, said: "The UK government wants to shoot England’s badgers. We want to vaccinate them – and save their lives."
The leaked draft ruling said that the advert was misleading because consumers were likely to interpret a claim in the advert to mean that all badgers would be eradicated in cull areas.
But a spokesman for the ASA said: "The ASA council is the jury that decides whether advertisements have breached the advertising codes. It has yet to make a decision in the case involving the RSPCA advert. Once it has reached a decision, we will publish our findings."
He said that the council was likely to make its decision shortly and could change the findings of the draft recommendation by the investigations executive.
It is understood that the RSPCA does not intend to run the advert again.
An RSPCA spokesman said: "No decision has been made by the ASA at this time and therefore we are unable to comment."