GENEVA -- The World Health Organization has approved the emergency-use listing of Johnson & Johnson's COVID-19 vaccine, the UN agency said on Friday, broadening access to the shots.

It is the third COVID-19 vaccine after the two-shot regimens of Pfizer/BioNTech and AstraZeneca to receive backing from the WHO, and the first to be done in a single injection.

The listing covers use in all countries and for roll-out of the vaccine platform COVAX and comes on the back of European Medicines Agency (EMA) authorisation announced on Thursday.

"Every new, safe and effective tool against COVID-19 is another step closer to controlling the pandemic," WHO Director-General Tedros Adhanom Ghebreyesus said in a statement.

"But the hope offered by these tools will not materialize unless they are made available to all people in all countries."

The WHO also welcomed the one-shot administration as facilitating vaccination logistics.

J&J's chief scientist Paul Stoffels told Reuters on Thursday the company expects to produce up to 3 billion doses of the vaccine next year, after previously pledging to deliver 1 billion globally by the end of 2021.

The WHO said that, under an emergency-use listing, companies have to commit to generate further safety and efficacy data to enable full licensing.