Angola, Venezuela and Malaysia are virtually assured to win support from the 193-nation UN General Assembly as they are running unopposed from their region.
That left two seats to be filled by the three competing countries which sent their foreign ministers to New York this week to lead a last-ditch lobbying campaign for votes.
For the contenders, a council seat is the ultimate diplomatic prize, raising a country's profile several notches, boosting influence and providing knockoff benefits in bilateral ties.
Countries must garner support from two-thirds of those present to win a seat.
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New Zealand's Prime Minister John Key sounded upbeat ahead of the elections, the culminating moment of years of campaigning for the country.
"It's been a 10-year campaign, we've run a very good campaign and we've done everything we possibly can," Key told reporters in Wellington.
"We're seen as a good, honest, trustworthy country that brings its independent foreign policy to the table."
Spain's Foreign Minister Jose Manuel Garcia-Margallo has pointed to his country's peacekeeping contribution in the campaign that saw King Felipe discuss the bid when he met with President Barack Obama in New York last month.
The elections come at a busy time for the council, which is grappling with crises on many fronts, from the jihadist offensive in Iraq and Syria, to the Ebola outbreak in West Africa.
Russia's actions in east Ukraine, conflicts in Syria, South Sudan and Central African Republic and the faltering Israeli-Palestinian peace process are also at the top of the council's agenda.