The Chinese government has attacked Australia over its support for an investigation.
"Now, we don't know about the lab and whether that was the initiation of this or not," Mr Morrison said.
"It may well have been, it may not have been. I don't have a view either way and I'm not in a position to make that judgement."
He said the world "deserved" answers.
WHO Director-General Tedros Adhanom Ghebreyesus has said he is asking China to be more transparent as scientists search for the origins of the coronavirus.
Dr Tedros said getting access to raw data had been a challenge for the international team that travelled to China earlier this year to investigate the source of COVID-19.