Helen Clark's standing in the preferred Prime Minister stakes has not been hurt. Photo / Mark Mitchell

Helen Clark's standing in the preferred Prime Minister stakes has not been hurt. Photo / Mark Mitchell

Labour's support in Auckland has dropped dramatically in the Herald's latest DigiPoll survey after a month in which violence in South Auckland and soaring petrol prices dominated the public's attention.

The June Herald-DigiPoll shows Labour's support in Auckland has dropped to 28.2 per cent - 10 points down from last month when it was sitting on 38 per cent support.

It is also well behind National, which 58 per cent of decided voters in Auckland supported.

National also increased its nationwide support to 54.9 per cent - its highest level since the Herald-DigiPoll survey began - and widened the gap between the two parties from 15 points in May to 22.5 points this month.

Labour's nationwide support has dropped four points since last month to 32.4 per cent, but the drubbing in Auckland - often described as the place elections are won and lost - will be of major concern for the party.

However, Helen Clark's standing in the preferred Prime Minister stakes has not been hurt - she rose to 45 per cent, while John Key dropped one point to 46 per cent.

The polling period took in a month dominated by crime following a spate of homicides and violence in South Auckland. Yesterday, a spokeswoman for the Prime Minister said this had clearly impacted on the polls.

However, she said Helen Clark's leadership on the matter was reflected in the preferred Prime Minister rankings.

National Party leader John Key said Labour's lack of action on violent crime had lost it support.

"This confirms the trend in other polls that people are rejecting Labour's economic management and are frustrated by the increasingly violent society for which it has no answers."

The economy continued to rate as the top issue likely to affect respondents' vote (23.8 per cent).

But public concern about crime saw law and order selected as the next issue most likely to affect voting, rising to nearly a quarter of respondents (23.4 per cent) - up from just 11 per cent in May. It overtook tax cuts (19 per cent) as the second biggest issue.

Among the minor parties, NZ First received a boost to 3.3 per cent - tantalisingly close to the 5 per cent threshold for automatically qualifying for seats in Parliament - after the month's emphasis on crime and the Super Gold Card gains leader Winston Peters secured in the Budget.