National has moved its campaign into rural New Zealand as it goes for the regional vote.
It's gunning for Labour over its policy to bring farmers into the Emissions Trading Scheme and says proposed new taxes will hit the regions hard.
"It's just another big uncertainty and it's aiming at the wrong target - it apparently won't be paid in places where there's no irrigation but where there are still water quality issues," he said.
"There's a good deal of resentment that Labour and the Greens have suddenly discovered water quality."
"These are people who have worked on it intensively, not just farmers, for a number of years now and they're being lectured by a bunch of people who haven't been here and have no understanding of a process that's been shown to be effective."
As Mr English was speaking, his senior spokesmen released National's plan for regional New Zealand.
Economic development spokesman Simon Bridges and primary industries spokesman Nathan Guy said voters had a clear choice between "two very different visions".
"Labour wants to hit our regions with new taxes that would slow New Zealand down, as well adding farmers to the Emissions Trading Scheme," they said.
"They want to risk our success through unclear policies and higher taxes, and that's not good enough."
Labour intends bringing farmers into the ETS during its first term, which means they'll have to pay for pollution, although 90 per cent of the cost will be carried by the government.