SYDNEY -- In a dawn ceremony at parliament house, Papua New Guinea (PNG) raised its national flag to mark 40th anniversary of independence from Australia's colonial rule on Wednesday.

Australia granted PNG independence in 1975 after a almost 60- year of colonial rule.

Local media reported tens of thousands gathered, wearing the national colors of black, red and yellow for the ceremony in Port Moresby.

PNG Prime Minister Peter O'Neill told the crowd the nation is also celebrating thousands of years of rich tribal history and culture.

Though PNG is facing economic and environmental difficulties, the Pacific nation would face up to present and future challenges with "courage and determination," O'Neill said.