UN Secretary-General Antonio Guterres has expressed concern over inequality in sharing and distribution of Covid-19 vaccines, pointing out that more than half of the world's countries have not met vaccination targets.

In his last press conference of the year in New York, the UN chief said as the fast-spreading Omicron variant raged on, the inequalities keep rising.

Vaccine inequity is giving variants a free pass to run wild, ravaging the health of people and economies in every corner of the globe, the secretary general said.

"It is becoming clear that vaccines alone will not eradicate the pandemic. Vaccines are averting hospitalisation and death for the majority who get them and slowing the spread. But transmissions show no sign of letting up. This is driven by vaccine inequity, hesitancy and complacency," APP quoted the UN chief as saying.