Over 50% of women do not know that drinking alcohol when pregnant could harm their unborn child, politicians have been told.
Speaking to Parliament's health select committee Law Commission president Sir Geoffrey Palmer said 55% of women think it is okay to drink during pregnancy.
"That figure is concerning."
The drinking rate among women of child-bearing age is increasing and a major barrier is that education campaigns will not work, Palmer says.
Policy analyst Susan Joy says for many young women the damage is done before they know they are pregnant.
One solution is to change the binge drinking culture among young women, she says.
Alcohol isoften a factor in unwanted pregnancies, abortion rates and sexually transmitted diseases with schools reporting an increase in services associated with these issues on Mondays - following a weekend of partying.
Once a woman knows she is pregnant, advice could be given through primary health carers, Palmer says.
Fetal Alcohol Spectrum Disorder (FASD) is the name given to a range of birth defects resulting from prenatal alcohol exposure
The disorders are all caused by mothers drinking during pregnancy and are not genetic, inherited or curable, the Alcohol Liquor Advisory Council's (Alac's) website says.
Birth defects can include growth retardation, central nervous system dysfunction, characteristic facial malformations, heart and kidney defects, hearing and sight impairments, limited joint movement, hernias, cleft lip or palate and brain damage.
Alac early intervention manager Sue Paton says Palmer is quoting figures that came out of a report they commissioned in 2007.
The research found only 40% believed women should abstain altogether from drinking during pregnancy. Half of the women surveyed said one drink or less was safe to be consumed on a typical drinking occasion in pregnancy.
"It really is a concern because there is no known safe limit and some children have been damaged with relatively small amounts of alcohol.
"There has been inconsistent medical advice around it."
The Ministry of Health and Alac both advise "not to play Russian roulette" and for expectant mothers to avoid alcohol altogether.
