Expert warns governments not to implement tax cuts without funding plan as UK's Liz Truss reveals she won't slash spending

A financial expert has called on governments around the world not to implement tax cuts without having a sufficient plan as to how they will be funded.

It comes after UK Prime Minister Liz Truss revealed she won't cut government spending to pay for her promised tax cuts. 

The UK's financial markets have been under strain since late last month when finance minister Kwasi Kwarteng announced 45 billion pounds (NZ$89b) of tax cuts, without saying how they would be paid for. 

"What we will make sure is that over the medium term the debt is falling but we will do that not by cutting public spending but by making sure we spend public money well," Truss told parliament.

At home, National leader Christopher Luxon wants to trim 14,000 public service jobs to fund his party's $3 billion-plus tax cut package, in order to save $2b a year, if elected. 

While National believed its tax cut plan differed from the UK government's policy, Milford Asset Management portfolio manager Will Curtayne said the situation in Britain should be a warning to other countries.

"It's a little bit of a warning shot across the bells of governments all over the world - us included - that, hey, if you're going to give out more money to the population and the areas affected by living costs and inflation… make sure you figure out how you're going to fund it," he told AM on Thursday.

Curtayne said governments couldn't just turn on "a tap that goes forever with no repercussions".

"You might find that if you don't have a complete plan that says how you're going to pay for this support, then we could see the New Zealand dollar come under pressure."

Meanwhile, Curtayne pointed to more market volatility in the near future.

"The good news for us is that there isn't too much debt in households or businesses around the world," he said. "This is different from the crisis we went through in 2009 and 2008 that really affected the financial system - I think we're in a safer place but it's still a little bit of a rocky path to travel."

UK Prime Minister Liz Truss and Chancellor Kwasi Kwarteng.
UK Prime Minister Liz Truss and Chancellor Kwasi Kwarteng. Photo credit: Reuters

While Prime Minister Jacinda Ardern has said Labour wouldn't follow National's idea of scrapping the top 39 percent tax bracket - introduced by her Government - she would not rule out cuts at election 2023. 

National's fellow right bloc party ACT also wants to implement tax cuts, funding them by "reducing the size of the bureaucracy" - saying it "wouldn't touch a single dollar of health, education, police or any frontline service". 

Leading economist Cameron Bagrie, meanwhile, believed tax cuts weren't the way forward for New Zealand - but did want to see brackets adjusted to match inflation.