The new civil detention orders would be issued by a High Court judge against prisoners deemed to be at imminent risk of serious sexual or violent reoffending. National estimates the orders would apply to between five and 12 offenders in a 10-year period.
On the same day that National released its law and order policy, Labour said it aimed to lift paid parental leave to six months - and support for that is more divided, with 51.5 per cent for and 44.5 per cent against.
More controversially, Labour decided to reverse its opposition to giving the In Work Tax Credit to beneficiaries with children, which 54 per cent oppose and 36.9 per cent support.
National has yet to release its education policy but its flagship policy in the first term, National Standards for primary schools - reporting to parents every six months against a set standard - finds favour with most voters, though not overwhelmingly.
Only 60.5 per cent say it is a good idea and should stay, whereas 24.7 per cent believe it is a poor idea and should go, and 14.8 per cent didn't know or said nothing.
But given that Labour has so fiercely opposed the policy, it is more surprising that nearly half of Labour supporters, 49 per cent, believe it is a good policy and should stay. The greatest support is among New Zealand First supporters, with 85.7 per cent.
Today's Herald DigiPoll survey shows a big jump in support for New Zealand First to just below 5 per cent and a lift in support for leader Winston Peters as preferred Prime Minister, up from 4.3 per cent to 5.5 per cent. The samples for smaller parties are low and should be seen as indicative but polling shows disproportionate support for the party and its leader among males, 6.9 per cent as opposed to 4.9 per cent generally, and from outside Auckland.
It also shows a lift from older voters. Last week 7.5 per cent of voters aged 65 and over supported New Zealand First; this week it is 10.2 per cent of the same age group.