The New Zealand sharemarket has suffered its biggest single-day fall in nearly two years, sliding nearly 3 per cent, as Russia goes to war against Ukraine. 

The announcement by President Vladimir Putin on Russian television sent jitters through the global markets: "I have decided to conduct a special military operation [in Ukraine]". 

He warned other countries that any attempt to interfere with the Russian action would lead to "consequences they have never seen." 

By 5pm, the S&P/NZX 50 Index had slumped 337.11 points or 2.78 per cent to 11,797.3 – the lowest level since September 25, 2020, when the index sat at 11,797.08. 

It was the worst trading day since March 23, 2020, when Covid-19 first struck and the index plummeted 7.59 per cent, but made up a lot of the losses the next day. The other previous big single-day fall was on July 9, 2020 when the index fell 2.28 per cent. 

Most major stocks were down, including Meridian Energy down 5 per cent, Infratil down 4 per cent, ANZ down 3.8 per cent, Ebos down 3.6 per cent and F&P Healthcare down 3.2 per cent. 

At the same time, the Australian S&P/NZX 200 Index was down 3.14 per cent to 6979.5 points. On Wall Street overnight, the Dow Jones Industrial Average neared the correction mark with a 1.38 per cent fall to 33,131.76. 

The other indices S&P 500, down 1.84 per cent to 4225.5 points, and Nasdaq Composite, down 2.57 per cent to 13,037.49, are already in correction territory. 

Jeremy Sullivan, investment adviser with Hamilton Hindin Greene, said the New Zealand reporting season had been robust, but overshadowed by the geo-political situation. 

"Diplomacy has gone out the window with the Russian invasion and any further escalation will make matters worse," Sullivan said.