Facebook founder Mark Zuckerberg, Microsoft billionaire Bill Gates, and celebrities including Bono and Charlize Theron have launched a declaration with an aim to give internet access to everyone by 2020.

The declaration was part of Zuckerberg's launch of the Connect The World campaign in partnership with One, an organisation advocating for the fight against poverty.

"When people have access to the tools and knowledge of the internet, they have access to opportunities that make life better for all of us," the declaration said.

"The internet belongs to everyone. It should be accessible by everyone."

Zuckerberg made the pledge to the United Nations on Saturday to make giving universal internet access a global priority.

On a Facebook post, Zuckerberg said internet access is essential, noting that for every 10 people that are connected to the internet, about one person is lifted out of poverty.

"If we connect the more than four billion people not yet online, we have a historic opportunity to lift the entire world in the coming decades," he wrote.

Other signatories included co-founder of Wikipedia Jimmy Wales and Mo Ibrahim for the Mo Ibrahim Foundation.

Jamie Drummond, co-founder and global executive director of One, added that internet access is a catalyst to "freedom, fairness, and dignity".

"Every country must now agree an urgent plan to implement the Global Goals, and mission-critical within those strategies is connectivity for all," he said.

"The Pope and Malala have spoken eloquently about the one world and one family we're all a part of, and the internet, at its best, facilitates that unity. But when three billion are left beyond the internet, they are left behind and left out of that family. That must change and fast."

In February, Facebook's Internet.org app launched in India to offer free access to a set of websites for users in six states; however it has since come under fire over net neutrality concerns.

Zuckerberg had also announced plans that Facebook would open Internet.org to more websites, provided they are approved by the social network, and meet certain restrictions, such as offering slimmed-down versions of their content without JavaScript, SSL, iFrames, video, Flash, and Java.