Forsyth Barr broker Ken Lister said the NZX-50 was feeling the benefits from overseas developments.
"While the New Zealand economy is still fragile, investors are taking a longer-term view and looking at companies that look cheap in terms of price to value and with positive earnings outlooks.
"With a low interest rate environment, investors are moving back into higher growth assets. That's what's needed to get some volume back into our market."
The positive trend in offshore markets and Portugal's recent successful bond auction continues to reassure investors that the global economy was improving and therefore company earnings, off lower forecasts, were likely to improve, Mr Lister said.
The benchmark index rose 19.38 points, or 0.6%, to 3353.97 as at midday on turnover of $28.9 million.
It closed at 3374, up 40 points.
Portugal's successful fundraising in the bond market, and at a lower cost for its 10-year debt issue, coupled with encouraging euro zone industrial production data, helped lift the value of the common currency euro, he said.
Attention now turned to debt auctions today in Spain and Italy which would also be watched for signs of contagion.
Analysts expected the sales to go through without a major hitch, but at elevated costs.
But little had changed to the view that Portugal would continue to struggle and would ultimately follow Greece and Ireland in seeking aid from the European Union and International Monetary Fund, Mr Lister said.
Portugal Prime Minister Jose Socrates said on Wednesday Portugal had no plans to seek a bail-out and the Government was doing everything possible to avoid doing so.
The successful Portuguese auction found favour with global markets.
The Nikkei stock average rose to a fresh eight-month high for a second consecutive day, European and United States stocks were boosted.
The benchmark Nikkei was up 0.8%, or 84.81 points, at 10,597.61. That was its highest intraday level since May 13, 2010.
The Australian stock market opened strongly following positive leads from offshore trading overnight, with all key indices and commodities prices higher.
US stock markets also rose to their best finish since 2007-08, buoyed by Portugal's bond auction success and jumps in banking and energy stocks.
The Dow Jones Industrial Average rose 83.56 points to 11,755.44, its highest closing level since August 11, 2008.
The broader S&P 500 index added 11.48 to reach 1285.96, a level last seen at the end of August, 2008, while the tech-heavy Nasdaq Composite index put on 20.5 points to 2737.33, its best close since November, 2007.
