South Sudan's parliament speaker proclaimed the fledgling state's independence on Saturday, marking its birth as the world's newest nation and splitting Africa's largest country in two.

"We, the democratically elected representatives of the people, based on the will of the people of South Sudan, and as confirmed by the outcome of the referendum of self-determination, hereby declare South Sudan to be an independent and sovereign nation," James Wani Igga announced.

The independence declaration was read out out in front of dozens of heads of state and foreign dignitaries and tens of thousands of cheering southerners.

South Sudan's national flag was then raised, to wild applause, tears and song.

"We shall never, never surrender," the crowd chanted, as people whistled and wiped tears from their eyes.

"I should cry for the recognition of this flag among the flags of the world," shouted one tearful man.

The declaration of independence affirmed the new state's democratic and multi-ethnic and muti-confessional character, and its commitment to friendly relations with all countries "including the Republic of Sudan", Igga said.