The China-backed Asian Infrastructure Investment Bank (AIIB) said on Saturday it had approved seven new members to join the bank, a day before China's biggest diplomatic event of the year kicks off.

Leaders from 29 countries will attend China's new Silk Road forum in Beijing on Sunday and Monday, an event orchestrated to promote President Xi Jinping's vision of expanding links between Asia, Africa and Europe underpinned by billions of dollars in infrastructure investment.

Delegations from around the world will attend including the United States and North Korea.

The new members are Bahrain, Bolivia, Chile, Cyprus, Greece, Romania and Samoa, bringing the bank's total membership to 77 countries.

The bank's president Jin Liqun held a joint press conference with Chilean President Michelle Bachelet to announce the new members.

"Better infrastructure across Asia will allow Chilean goods to access new markets, more investment in Chilean infrastructure in turn will further bind together the two great continents of Asia and Latin America," said Jin.

"We think there are a lot of projects that can link Asia with or through Latin America," said Bachelet, adding that she had spoken with Jin about the possibility of investing in a Trans-Pacific optic fiber cable to improve digital connectivity between Asia and Latin America.

"The cable could be considered a part of the 'One Belt, One Road Initiative' and transform the Pacific Ocean into a bridge between our regions," she added, using another name for China's "Belt and Road Initiative" or new Silk Road plan.

Other investments could include tunnels and highways across the Andes Mountains and ports to link Latin America and South America to Asia, Bachelet added.

Thirteen prospective new AIIB members from around the world, including Canada, were approved in March.

"Expanded membership to Africa, Europe and South America, along with the addition of further members in Asia shows the level of global commitment towards the bank's mission and illustrates the momentum that has gathered since 20 countries signed initial memoranda on establishing the bank less than three years ago," said Jin.

The multilateral institution, seen as a rival to the Western-dominated World Bank and Asian Development Bank, was initially opposed by the United States but attracted many U.S. allies including Britain, Germany, Australia and South Korea as founding members.