National has maintained a constant barrage of criticism against Labour for its vagueness on taxes, including a capital gains tax, water tax, inheritance tax and land tax.
Mr Joyce continued that criticism yesterday before Green Party supporters and trade unionists suggested he was planning a hike in GST.
On Twitter, Mr Joyce replied: ''For the benefit of assorted left-winged activists with nothing better to do - there will be no increase in GST under @NZNationalParty.''
That statement was met with questions about whether it was the same as that of former prime minister Sir John Key, who said National wanted to cut taxes, not raise them, before lifting GST to 12.5%.
The Council of Trade Unions and BusinessNZ entered the campaign yesterday, calling on National and Labour to clarify their employment policies.
Mr Joyce, also National's campaign manager, said New Zealand's economy was growing strongly. As a result, more permanent jobs were being created and family incomes were growing.
''Labour wants to stall our economic success through heaping at least seven new taxes on New Zealanders just when they're starting to get ahead.
''We simply don't need to impose a capital gains tax, land tax, regional fuel tax, extra income tax, water tax or inheritance tax. We also don't need to bring farming into an ETS [emissions trading scheme] when no other farmers worldwide are included.''
Labour finance spokesman Grant Robertson hit back, saying it was time for Prime Minister Bill English and Mr Joyce to stop the scaremongering and lies and front up to New Zealanders about the impact of their tax cuts.
''Bill English has no credibility on tax issues. He was the finance minister in a government that increased GST after specifically ruling that out in the election campaign.''
National had introduced 18 new taxes, levies and charges, including one on the capital gain from an investment property within two years.
Again, National never talked about that in an election campaign, he said.
Labour would reverse the tax cuts proposed by National that would see $400million go to the top 10% of New Zealanders. Those tax cuts were reckless and irresponsible at a time when so many of the big issues facing New Zealand were getting worse, he said.
