Archbishop Hart said Tuesday that embryonic cloning was "always unethical" and there was "total opposition" from the Catholic Church.
Bracks has said his Catholic faith has not dissuaded him from proceeding with the bill.
"To allow human embryos to be deliberately created and then destroyed for scientific research is always unethical," the archbishop was quoted as saying. However, he added, the Catholic Church does support ethical forms of stem cell research based on adult stem cells, as well as those derived from the blood of the umbilical cord.
The bill was introduced in State Parliament last night, and opposition was voiced at a government caucus meeting yesterday. Former minister Christine Campbell reportedly spoke against the bill for more than 20 minutes.
Campbell said that benefits had not been extensively proven in animal testing and legalization of the procedure would put fertile women at risk by harvesting their eggs.
She and fellow Labor MP Tammy Lobato have organized a forum for MPs on Thursday to learn more about the issue before voting.
Under the proposed legislation, researchers would be allowed to clone human embryos for medical research through somatic cell nuclear transfer, commonly known as therapeutic cloning. But researchers would not be allowed to merge an egg with sperm to create an embryo.
This research is already practiced in the U.S., Britain, Sweden, Japan, China, India and Israel.
.- Archbishop Denis Hart of Melbourne intends to make a personal plea to Premier Steve Bracks to abandon his plan to pass a bill that would allow therapeutic cloning of human embryos. The archbishop said he would seek talks with the premier once details of the bill were known, reported The Age.