Since July, 18 people have died from cholera and 240 others have contracted the disease in Morobe Province on the country’s north coast.
At the same time, in the same province, authorities are also battling an outbreak of dysentery that has killed 29 and infected 400.
PNG Health Minister Sasa Zibe said the emergency declaration will give health authorities greater powers to contain the outbreaks.
They will be able to shut down facilities like restaurants if they do not comply with sanitation standards.
They will also be able to prevent people from moving to and from infected areas.
Australia is providing assistance in the form of water purification tablets and water containers.
