Prime Minister Jacinda Ardern announced $NZ27 million ($A24.3 million) for the Pacific nation, with climate investments to be decided in tandem between the two governments.
"This funding will help build Samoa's resilience to the impacts of climate change and its transition to a low emissions economy," Ms Ardern said.
Ms Ardern is in Samoa on a two-day visit on the occasion of the 60th anniversary of both Samoan independence and the signing of a Treaty of Friendship between the two countries.
The visiting New Zealand delegation - including the opposition leader, other MPs, business and religious leaders - were the first arrivals after Samoa relaxed its border regime on Monday to allow international tourists to visit again.
On Monday night, officials from both countries enjoyed a lavish feast outside the Robert Louis Stephenson Museum in the lush forested hills of the capital.
Samoa Prime Minister Fiame Naomi Mata'afa said she "felt an emotional twinge" on the anniversary, given her father - the first Samoan prime minister - signed the treaty.
"The 60-year friendship has withstood the test of time and constant debate," she said.
"The diplomatic bonds between Aotearoa New Zealand and Samoa continue to evolve, but ... may this cooperation pave our common paths into the future."
Despite the enduring friendship, there are a few bugbears.
Fiame Mata'afa raised the challenges with seasonal worker programs and difficulties with labour shortages in Samoa, which she said reduced the skilled workforce available to Samoa's tourism and public sector.
Ms Ardern said her government would review the scheme.
"We want the scheme to benefit both Samoa and New Zealand ... it was primarily intended to be an employment opportunity for those in Samoa who are unemployed," she said.
The pair also discussed regional issues, though Ms Ardern said there had been no movement on the biggest challenge facing the Pacific Islands Forum: the withdrawal of Kiribati.
"All sides have said the door remains open," Ms Ardern said.
With borders largely closed for more than two years, Samoa's economy has been hurt by the loss of tourism revenues.
There is also evidence to suggest the pandemic has also produced a downturn in remittances entering the country from the Samoan diaspora, given worsening global economic conditions.
Ms Ardern said Samoa requested support for the rebuilding of Savalalo Market, which was destroyed by fire in 2016.
The site is currently concreted up, though officials have placed a giant banner there which reads "Talofa Lava - Kia Ora" and "our spirit of friendship lives on", welcoming the Kiwi visitors.
"The rebuilding of the market signifies our focus on economic recovery through support to small business, local enterprise, and women's entrepreneurship," Ms Ardern said.
"It is at the heart of Apia's community and economic life, as well as formerly being a major tourist attraction. We are proud to support the government of Samoa re-establish it."
New Zealand is contributing $NZ12 million ($A10.8 million) towards the market.
The $NZ15 million ($A13.5 million) climate funding will come from New Zealand's climate finance commitment, which averages at $NZ325 million ($A293 million) annually, half of which has been pledged to the Pacific.
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