"In this kind of environment having stable government is a good thing, especially given we have a disciplined fiscal plan," he said.
Investors had grown nervous about the outcome of the election after a bout of late polls showed National might struggle to cobble together a working majority due to a late surge in support for New Zealand First.
Saturday's result means Key will be able to press ahead with plans to overhaul the welfare system, sell down holdings in a handful of state-owned enterprises, and introduce competition to Accident Compensation Corp's work book.
Craig Brown, senior investment analyst at OnePath (NZ), said the result is what the market was looking for and "should be favourably received."
"In terms of the short-term, this will be seen as a positive outcome," he said. "It means we can continue on with the existing leadership, which has been doing a pretty good job in pretty difficult and volatile times."
ANZ's Goh said the result might see investors return to the government bond market after they were spooked by last week's polls. The yield on 10-year government bonds rose 5 basis points to 4.045 percent.
"People opted to wait till after the weekend, and with the clear outcome, people will probably come back from the sidelines," he said.
The plan to sell down just under half the government's holdings in electricity generators won't be derailed with veteran politician and opponent Winston Peters and NZ First returning to Parliament, Brown said.
"Winston will be on one side of the House throwing mud around," but doesn't have the numbers to prevent it, Brown said.
Earlier this year, Key signalled the government planned to sell down its stake in the three electricity retails Genesis Energy, Meridian Energy and Might River Power, coal miner Solid Energy and national carrier Air New Zealand to just over half, raising as much as $7 billion which it will use to fund other infrastructure projects.
Brown said listings on the stock exchange will deepen the bourse and help improve investor confidence, which is struggling in the current global environment.
Even though the international volatility might drag down the maximum price the government can get for the partial floats, the defensive nature of the electricity stocks and similarities to listed power companies Trust Power and Contact Energy should add some certainty for investors, Brown said.
The Maori Party, another potential support partner for the government, campaigned on opposing asset sales, though co-leader Pita Sharples said they would be willing to negotiate special access for iwi if the programme was to proceed.
Brown said having Maori interests on the share registry should help ensure there's enough demand for the sales, and could be done via a share issue as part of a Treaty of Waitangi settlement, with heavyweight iwi Tainui and Ngai Tahu negotiating clauses that would lift their pay-outs if total settlements with all Maori exceed $1 billion.
If the government's asset sale programme is a success, that could see local government agencies opt for similar measures to free up capital to pay for new infrastructure, Brown said.
Earlier this month, Auckland Council, the country's biggest local government body, was put on CreditWatch negative by rating agency Standard & Poor's over the city's planned increase in spending, particularly on transport.
Assets that could potentially be sold include Ports of Auckland, which was previously publicly listed, and Watercare Services.
