FRANKFURT, Sept 22 (Reuters) - The European Central Bank will discuss whether to raise its regular bond purchases when its pandemic-fighting scheme ends, ECB policymaker Madis Muller said in an interview published on Wednesday. "I realise that it would be a problem if there is a very sharp cliff effect at the end of the pandemic emergency purchase programme (PEPP),” the Estonian central bank chief was quoted as saying by Bloomberg. He reportedly added that increasing the ECB"s Asset Purchase Programme would be "part of the discussion we will have on how to phase out PEPP and what it would mean for asset purchases going forward".