The Asian Development Bank says rapid population growth is putting increasing pressure on the infrastructure of Tonga's capital, Nuku'alofa.
The ADB, along with the Australian government aid agency, AusAID, is providing a multi million dollar grant to help the Tonga government address the problems.
Together the two agencies are giving 12 and a half million US dollars, with Tonga providing another two million.
The ADB says the project will target six different components of Nuku'alofa's urban services, including water supply and solid waste services.
It will also bolster community awareness of urban services such as planning, household management of solid waste, and the public health benefits of safe waste disposal.