Vanuatu, Fiji and Samoa are among eight prescribed countries whose passport holders will be allowed to hold dual citizenship in Papua New Guinea.
PNG's Minister for Foreign Affairs and Immigration Rimbink Pato launched the PNG Citizenship and Dual Citizenship Pathways system.
It means citizens of Vanuatu, Fiji, Samoa, Australia, New Zealand, Britain, Germany and USA can now apply for dual citizenship in PNG.
Other foreign nationals eligible to apply for dual citizenship in PNG include investors, people married to Papua New Guineans, long-term residents, sportsperson and people with PNG descent.
The minister said the benefits of dual citizenship were many, including the prospects for fostering more investment in PNG.
Mr Pato said there were two categories of people who could apply for dual citizenship.
The first category covers people from the eight prescribed countries to apply for dual citizenship with PNG.
The second category is for PNG citizens opting to hold citizenship of another prescribed country while also maintaining their existing PNG citizenship.