Auckland solar energy company Sunergise International has received US$2 million (NZ$2.3m) funding from World Bank Group member IFC.
Sunergise co-founder Lachlan McPherson said the details of the deal were commercially sensitive, but IFC was taking a "substantial minority stake" in the company.
IFC's investment would allow Sunergise to scale up its business and expand solar installations in New Zealand, Fiji and Papua New Guinea, he said.
Sunergise owns and operates solar power systems that are installed on customers' premises under a fixed-period supply agreement.
Sunergise chief executive Paul Makumbe said about 50 per cent of the power supply in the Pacific was diesel-generated and could readily be replaced with solar power.
While the region was almost completely dependent on imported fossil fuels, renewable energy resources were abundant and most Pacific countries received an average of six hours of sunshine every day, Sunergise said.
IFC East Asia-Pacific director Sergio Pimenta said the investment in Sunergise would help the global development institution provide more people with energy in places where there was little or no access to an electricity grid.
"Offering less expensive, cleaner power to customers, with no upfront capital outlay, will provide significant benefits in countries such as Papua New Guinea, where as little as 12 per cent of the population has access to power," Pimenta said.