Rory O´Hanlon, a retired High Court judge, has questioned the way the referendum is being handled and challenged the definition of abortion devised by the government, the London paper said.
His sharpest criticisms are directed at a section in the bill to protect the unborn, which defines abortion as the "intentional destruction by any means of unborn human life after implantation in the womb of a woman."
This definition was chosen by the government to ensure that use of the morning-after pill and IUDs would be legally permissible.
Some observers, however, recognize that the morning-after pill can also act as an abortifacient -- a drug that causes abortion -- and the Irish Medicines Board has refused to license its use for this reason.
O´Hanlon questions the way this definition deals with the issue of when life begins. The Catholic Church has always maintained that life begins at conception, and the former judge said he envisaged the Church having problems with the definition.
The government is planning a constitutional amendment accompanied by legislation to protect the unborn. O´Hanlon believes this is too complicated and could create confusion among voters. He believes the issue could be resolved by an amendment to the constitution alone.
If the bill went to the people in its present form, O´Hanlon said he would have difficulty recommending its support.
While the main pro-life groups have given a qualified welcome to the referendum proposed by the government, there are signs that battle lines for the campaign are being drawn.
The Labor Party has criticized the proposal but is facing internal difficulties. Its party conference adopted a contradictory position, committing the party to oppose referendums while at the same time supporting a woman´s legal right to kill her unborn child, a right that could only come about through a referendum.
Fine Gael, Ireland´s main opposition party, has questioned the legal basis for the government´s approach but has yet to decide whether it supports or seeks to amend the proposal.