Mr Woodhouse said this morning he was reluctant to advise the New Zealand Police on operational matters, even though he has admitted he had some reservations about their proposed speed enforcement messages for summer when he was briefed about them last year.
"It's really important that the operational separation between politicians and the police is maintained," he told the Herald.
"We set the law, and it's over to police to uphold it. That's a really important constitutional principle that I didn't then and won't now breach."
Labour leader Andrew Little disagreed, saying the minister could have stepped in if he had doubts.
"If he's not confident that it's not the right thing to do then he as the minister has the power to say 'You shouldn't do that'. They wouldn't have made that announcement without his blessing."
The minister yesterday ordered a review of the police's public messaging on road safety over the summer period, saying it was important that campaigns were "understandable and unambiguous". The campaign was widely criticised by the public and agencies.
Police Commissioner Mike Bush had warned drivers that the 4km/h tolerance above the speed limit was no longer in place and motorists could be ticketed for driving 1km/h over the speed limit. But he also said individual officers would decide whether to issue tickets for drivers caught driving only a small amount over the limit.
Mr Little said the review looked "a bit flakey".
"It looks to me like he's now looking for a way out and ducking responsibility for a judgement that he took a couple of months ago."
Mr Woodhouse stood by the zero tolerance policy but said the police's communication of the policy had been confusing and had created "unnecessary anxiety" among motorists.
New Zealand First MP Ron Mark has called for any tickets issued to people driving slightly over the limit to be refunded.
Mr Woodhouse said this was "patent nonsense" and preliminary data showed the number of speeding tickets for people driving at 101km/h to 104km/h were "very, very low".
The results of the review were expected by the end of February and any potential changes would be in place before the Easter holiday
Seventeen people were killed on the roads over the Christmas-New Year period, more than double the 2013-14 toll.
- Isaac Davison of the New Zealand Herald
