Experts say increased testing accounts for some, but not all, of the rise.
Markets turned weaker as investors were forced to balance the positive impacts of economies reopening with the increased risk of a virus flare-up that goes with it.
On Wall Street overnight, the S&P 500 fell half a per cent and the Dow Jones Industrial Average dropped 0.8 per cent.
The New Zealand market followed that lead. This country's own difficulty keeping incoming Covid-19 cases contained at the border also reminded investors a second wave in NZ remains a present, if low, risk.
"Over the last week the news around the risk of a second wave, and what we are seeing locally in terms of re-emergence, has been detrimental," Sam Trethewey, portfolio manager at Milford Asset Management.
The recent weakness in travel stocks showed that investors were being put off by bad data, are were unlikely to let share prices continue to rise without a material improvement.
"After the strong recovery we have seen in April and May, it is difficult to see any more positive catalysts to push the market further."
Stocks directly exposed to travel took a tumble: SkyCity Entertainment fell 3.9 per cent to $2.74, Auckland International Airport dropped 3.4 per cent to $6.58, Air New Zealand fell 2.3 per cent to $1.475 and Tourism Holdings declined 1 per cent to $1.96.
A2 Milk led the market lower, falling 4.7 per cent to $19.38. Australian media today speculated the Kiwi dairy giant was seeking to buy producer Mataura Valley Milk for $400m. A2 confirmed it was in talks to expand manufacturing capability but didn't address the Mataura rumour directly.
Trethewey said today's share price movement was more related to the price settling after Friday's NZX 50 rebalancing and the stock's inclusion in the ASX 50 on Friday night. A2's share price rose 8 per cent last week.
Synlait Milk, which supplies all of A2's infant formula, fell 4.2 per cent to $7.14. Trethewey said A2 adding its own manufacturing capability would increase its negotiating power with Synlait.
Napier Port declined 2.8 per cent to $3.79 on its first day of trading as part of the NZX 50, giving up some of the rally it saw in the lead-up to its inclusion. The stock rallied 8.6 per cent last week.
Port of Tauranga held last week's 13 per cent gain at $8.09 today.
Kiwi Property fell 0.9 per cent to $1.07. Today the company announced it would resume paying dividends later this year as visitors to its shopping portfolio had recovered 1 per cent above pre-Covid levels.
Pushpay Holdings - which has now doubled in value this year after gaining another 14 per cent last week - climbed a further 5.1 per cent to $8.66, the day's biggest gain.
Fisher & Paykel Healthcare rose 2.2 per cent to $29.35. Trethewey said the healthcare manufacturer was attracting attention ahead of its annual earnings report next Monday. Investors would be looking closely to see if the sale boost from the pandemic would lead to long-term revenue gains.
Outside of the NZX 50, transport fleet tracking company Eroad fell 1.2 per cent to $3.25.
Jarden analysts today raised Eroad's target share price to $4.39, saying the company was operating in attractive markets and was supported by increased regulation in the transport space.
Correction: An earlier version of this report incorrectly stated Fisher & Paykel Healthcare's closing share price. Apologies for the error.
