Despite acknowledging that the Philippines is one of the oldest democracies in Asia, he said democracy in the country is a "work in progress" but stressed that Filipinos are free people.
Duterte made the statement as he virtually gave his speech during the last day of the Summit for Democracy on December 10. The summit was convened by US President Joseph Biden.
In his intervention, the President said the Philippine democratic agencies have always been threatened by a number of issues.
"While we are the oldest democracy in Asia, our system of governance is not perfect," he said.
"Corruption, poverty, and peace and order issues have always been and continue to be our major challenges. They weakened our institutions and deprived many Filipinos of democratic agencies," he added.
Despite this, Duterte said the Philippines has come a long way.
"Today, we have a vibrant democracy and an open and diverse society," he said.
"Freedom of expression and of the press are fully enjoyed and the regular transfer of power is guaranteed through free and honest elections," he added.
The President thanked the United States for convening the Summit for Democracy, especially at a time when the world is facing challenges, including the ongoing coronavirus (COVID-19) pandemic.
"These challenges call for the close examination of our democratic institutions while holding fast to the values and principles we have sworn to uphold," he said.