At 5593, the NZX50 reached its highest level since the index was launched on December 29, 2000, Craigs Investment Partners broker Greg Easton said. It closed at 5577.
The ASX200 reached its most recent high in November 2007 and was set to finish the year with a total rise of just 2.4% compared with 17.27% in 2013.
In contrast, the NZX50 had rolling annual average growth of 17.4% at the end of yesterday, he said.
The New Zealand sharemarket had been supported by a lower-interest-rate environment, with investors seeking better returns than those offered by term deposits.
''Every time the Reserve Bank governor [Graeme Wheeler] speaks, he becomes more dovish about interest rates. Investors take that as a signal to buy.''
Companies providing good dividend yields, along with infrastructure companies offering growth, were popular, Mr Easton said.
Port of Tauranga shares hit an all-time high yesterday and Auckland International Airport, which owns part of Queenstown Airport, was close to a record high.
Property stocks had been rising in value in the past six months but the past few weeks had been extraordinary, he said.
''Based on comments coming from Mr Wheeler, there may not be another interest-rate rise.''
Part of the demand in New Zealand was coming from a lack of sellers, with investors being prepared to hold on to high-yielding stocks rather than sell. Each day, there were more bidders than sellers, he said.
However, in Australia, the predominance of resource-based stocks had seen the Australian economy face massive deficit forecasts, Mr Easton said.
The continuing slump in oil prices was likely to provide more hurt for Australia, but it was not just oil stocks being sold down. Iron ore and coal producers were also struggling.
Federal Treasurer Joe Hockey was facing a decade of deficits, something unheard of in the history of Australia.
Reports from overseas said a drop in iron-ore prices had humbled resource-rich Western Australia and turned a part of Perth where mining companies were based into something of a ghost town as offices lay empty.
With its mineral abundance, the state helped steer Australia around a recession in the aftermath of the global financial crisis, Mr Easton said.
Western Australia had always seen itself as different, so sure of its importance to the national economy that it had threatened - just half in jest - to break away and join industrialising Asia, which bought its resources.
That headiness had now come to an end.
Last week, Western Australia forecast its first deficit in 15 years - a graphic illustration of the havoc plummeting commodity prices were causing to the wider $A1.5 trillion ($NZ1.57 trillion) economy as China's slowdown cooled a decade-long mining boom.
As recently as May, the state's conservative government was forecasting a $A175 million surplus in the fiscal year through June, a rosy estimate based on iron-ore prices averaging about 40% higher than where they stand at present.
On Monday, Western Australia revised the forecast to a deficit of $A1.3 billion based on new expectations iron ore would average $US75 ($NZ96.37) a tonne, not $US122.70.
Credit agencies in recent months stripped the state of its top rating.
Worried politicians were seeking to sell assets worth billions of dollars, ranging from ports to a wholesale fruit-and-vegetable market, but analysts said the state's balance sheet would remain stretched unless iron-ore prices recovered soon.
The reversal of Western Australia's fortunes has humbled the state, whose size would cover about a quarter of the continental US, Mr Easton said.
An offshoot of the differing economies was the growing strength of the New Zealand dollar against the Australian currency.
Yesterday, the dollar was trading at A95.80c, which would not encourage exporters, he said. Parity with the Australian currency was still a ''serious possibility''.
With Australia ranked as the top or second-top export market for New Zealand, there would be some concern, but Mr Easton said imports and travel to Australia would be cheaper.
The challenges for the New Zealand market in the next 12 months would be backing up the increase in asset prices with earnings.
If the Reserve Bank signalled a delay in interest-rate rises, there would be more support for the market, he said.
At a glance
• NZX50 reaches an all-time high yesterday of 5593, closing at 5577.
• Infrastructure companies spark investor popularity.
• New Zealand dollar reaches A95.80c.
• Western Australia forecasts first deficit in 15 years.
