The opposition is criticising the National Party's promise to lack at enacting tax cuts after the upcoming election in September.

Prime Minister Bill English set out his party's priorities at in a keynote speech National Party in conference in Wellington over the weekend.

National has already promised to reduce taxes from April next year by lifting the thresholds at which the bottom two rates apply.

As part of a broader family incomes package, that will lift the incomes of 1.3 million households by an average of $26 a week.

Labour Party leader Andrew Little claimed that after nine years in government, Bill English is looking at the 2020s and he's out of ideas.

"We actually need some of our big challenges fixed, not just more tax cuts," Little said.

"This is classic National Party - out of ideas, out of steam, an empty vessel, empty promises."

ACT Party leader and government support partner David Seymour is also taking the pledge with grain of salt, saying National's record on tax has been dismal.

"Last month, the tax cuts in the Budget were enough [but] they clearly weren't. National have got their polling back and found out ACT was correct, now they want to cut taxes more."

During the party conference, Bill English described Labour, the Greens, and New Zealand First as an unruly alliance, and a miserable group wanting shut down growth, trade, and opportunity.

New Zealand First leader Winston Peters, however, says English has a hydra headed monster of the Maori Party, United Future, and ACT, and a split between town and country in his own caucus.

"I think the Prime Minister would be better to talk about his own boat and his own motor, clapped out as the engine is, not whether we're doing our job," Peters said.