In a statement, Guterres said Sir Michael was Papua New Guinea's first Prime Minister who led the country to independence and to joining the United Nations in October, 1975.
"Sir Michael will be remembered for his pivotal role in the independence and foundation of Papua New Guinea, as well as his lifetime of public service dedicated towards building a prosperous and democratic country," wrote Mr Guterres.
"The United Nations is also grateful for his commitment to international cooperation and multilateralism.
"I extend my deepest condolences to the family of Sir Michael, as well as to the Government and the people of Papua New Guinea."