Kiwibank economists said the market responded positively to the package, which provided a backstop for businesses and reduced the risk of increased loan defaults.
"The Kiwi wholesale rate curve lifted a little and steepened a little. That's the markets way of inserting more growth and inflation into the forecast profile," they said.
Matthew Goodson, managing director of Salt Funds Management, said there was "get me out at any price" selling during the morning, which was absorbed during the day.
While the NZX50 rose at the time of the economic package, that coincided with a sharp rise in US futures and on the S&P/ASX200, which was up 3.4 per cent in afternoon trading.
"I wouldn't put the intra-day turnaround all down the package itself," Goodson said.
"Markets are so volatile that investors are keeping an eye on minute-to-minute price movements and haven't gone through the package in much detail yet."
Heartland Group Holdings led the market lower, falling 11.6 per cent to $1.07, its lowest level in five years.
Vista Group International sank 10.9 per cent to a record-low $1.55. The cinema analytics software maker today cancelled its dividend due to be paid next week to preserve its balance sheet. It also withdrew its 2020 earnings guidance as it struggles with the murky outlook for movie-goers around the world.
Gentrack Group dropped 10.7 per cent to $1.34 after the airport and utilities software developer suspended its annual guidance, citing the uncertainty caused by the global pandemic.
Auckland International Airport fell 2.3 per cent to a five-year low $5.10 after it cancelled next month's dividend payment and said it's reviewing its capital spending programme.
Air New Zealand shares remained halted at $1.54. The government's $600m aviation package specifically excluded support for the national carrier. Robertson, who is a shareholding minister in the airline, said the government is still in discussions with the company.
Goodson said without billions of dollars of government bailouts, airlines will not be able to survive the global rout in air travel. That makes it likely that Air New Zealand, Qantas Airways and Virgin Australia will all need recapitalisation.
"Given that the effect of the closure of our borders has only occurred in the last day or two, it is early days in terms of the impacts," he said.
Mainfreight increased 2.3 per cent to $30.18. The global logistics firm said its trading so far this year was ahead of the period in 2019, and that global freight trade lanes were still open.
Courier operator and data management firm Freightways climbed 11.3 per cent to $5.61 and Port of Tauranga rose 6.5 per cent to $5.75.
Greg Smith, head of research at Fat Prophets, said it was a "leap of faith to think that port volumes will recover in the near future."
Fisher & Paykel Healthcare fell 1.2 per cent to $24.90 despite the breathing respirator maker raising its earnings guidance due to a weaker kiwi dollar, and as the virus outbreak stokes demand for its homecare products.
Outside the benchmark index, New Zealand King Salmon decreased 1.7 per cent to $1.74 after it affirmed annual earnings guidance. It said it's working with logistics firms to keep markets open, using cargo aircraft and its frozen sea freight programme to make up for reduced passenger flights.
