KEY POINTS:
Sue Bradford's bill outlawing physical punishment of children is expected to pass its final reading in Parliament tonight with only five of the 121 MPs voting against it.
All of Labour, National, the Greens and New Zealand First are expected to vote for the bill.
The bill won National's support with the inclusion of a clause explicitly saying that in the case of minor and inconsequential offences, police should use discretion and prosecute only if they believed it was in the public interest.
Voting against the bill will be the two Act MPs, leader Rodney Hide and Heather Roy; two of United future's MPs, Gordon Copeland and Judy Turner, and the independent MP Taito Phillip Field.
The Act MPs come from a libertarian tradition and believe that the bill not only criminalises parents who smack but that it is an example of state interference in people's lives.
The other three are Christians, who have opposed the bill on the grounds that there is such a thing as a "loving smack" for correcting child behaviour and that even the compromise reached over prosecutions does not improve it enough to support it.
Mr Hide challenged National and Labour to make tonight's vote a conscience vote. Labour has whipped its MPs all along on the bill.
The bill will take effect a month from it receiving the royal assent, which means it is likely to take effect from mid-June.
Green MP Sue Bradford said yesterday that she hoped tomorrow's Budget would contain resources for an education campaign on the new law and for parent-help groups and programmes that promote alternatives to physical discipline.