The assembly’s communities, equality and local government committee had considered including the ban as part of a new law to tackle domestic violence.
However, Public Services Minister Leighton Andrews said it was the “wrong vehicle” to introduce such a law.
Committee chair Christine Chapman said she was disappointed the government “cannot yet do the right thing”.
In October 2011 assembly members voted in favour of banning the defence of “reasonable chastisement” for smacking.
But the then minister responsible for children, Gwenda Thomas, ruled out legislation before the 2016 assembly election, citing the need for preparatory work amid fears of “criminalising” parents.