"We think overall the level of contribution we are making around peacekeeping is about right."
New Zealand has about 80 military personnel and 30 police involved in peacekeeping duties.
Mr Key would not rule out providing more specialist support to UN peacekeeping missions such as intelligence help from the GCSB.
"It's never impossible. But we are already very actively engaged from a foreign peacekeeping perspective."
The push to change peacekeeping missions into better fighting units has been controversial because of the traditional view of them as non-partisan.
Mr Key said he had spoken to the UN head of peacekeeping while in New York and he had reported they had about 125,000 troops and set out the specialist areas where they wanted more support.
New York diary
Overnight
• Prime Minister John Key had his first one-on-one meeting with Fijian Prime Minister Frank Bainimarama.
• Key went to President Barack Obama's "Countering Isil" (Islamic State) summit with about 40 other leaders. Speakers included Obama and Iraqi Prime Minister Haider al-Abadi.
• Key attends Bill Clinton's "Clinton Global Initiative" summit, featuring Bill and Chelsea Clinton.
Tonight
• Foreign Minister Murray McCully will attend the Security Council's foreign ministers' meeting to discuss Syria.
• Key meets Helen Clark, former PM and head of the UNDP.
• Key speaks about the TPP and Chinese investment at an Asia Society breakfast.
Harmony breaks out as foes do lunch
Perhaps it was the lunar eclipse or the roses in the UN Rose Garden with names such as Peace and Hope that inspired the outbreak of harmony in New York between long-scrapping foes. Or perhaps it was just UN chief Ban Ki-moon trying to impose peace via seating plans at his luncheon.
As the cameras focused on Russia's President Vladimir Putin and US President Barack Obama toasting each other, further down the room Prime Minister John Key was doing the same with his own long-standing foe.
It appears Key has found himself on his way to a rapprochement of his own with Fiji's Prime Minister Frank Bainimarama. Until this year's General Assembly, the pair had never met face-to-face. Bainimarama was on the naughty seat from the 2006 coup until Fiji held elections in 2014, in which he was duly elected Prime Minister. And he boycotted the Pacific Islands Forum last month in protest at New Zealand and Australia's roles on it.
But at the UN the leaders had little choice. Seating plans meant they could not escape each other. The first meeting was a reception hosted by Japan's PM Shinzo Abe. Key seemed almost surprised to emerge unscathed. And early yesterday Key had his first formal leader-to-leader meeting with Bainimarama, noting he was the first New Zealand PM to meet him in almost a decade. Just like that, the Tepid War of the Pacific was over.
So it seems at least two countries will leave the UN with a better relationship than they began. In diplomat-speak there are varying levels of closeness - allies, friends, good friends, partners, enemies. Key and Bainimarama can now officially be declared frenemies.
