UN Secretary-General Antonio Guterres has warned that the world body was facing its own "1945 moment", noting that efforts must be made to "meet that moment".

"In this 75th anniversary year, we face our own 1945 moment. We must meet that moment," Xinhua news agency quoted Guterres as saying at a press conference at the UN headquarters in New York on Wednesday.

"We must show unity like never before to overcome today's emergency, get the world moving and working and prospering again, and uphold the vision of the Charter," he added.

The UN was established after the Second World War with the aim of preventing future wars, succeeding the ineffective League of Nations.

On April 25, 1945, 50 government representatives met in San Francisco for a conference and started drafting the UN Charter, which was adopted on June 25, 1945 and took effect the same year on October 24.

Pursuant to the Charter, the organization's objectives include maintaining international peace and security, protecting human rights, delivering humanitarian aid, promoting sustainable development, and upholding international law.

At its founding, the UN had 51 member states.

The membership now is 193, representing almost all of the world's sovereign states..