The second part of UN biodiversity summit COP15, set to take place in Switzerland in January, has been postponed over the new coronavirus variant Omicron, organisers said on Thursday.

"Uncertainties posed by the Omicron variant and resulting travel measures and restrictions" have forced physical meetings to be postponed, they said in a statement.

The Geneva meeting originally supposed to take place from January 18 to 22 could instead be moved to March.

In a sign of Omicron's threat, about 2,000 people, including 1,600 children, have been placed in quarantine after two cases of the variant were found on one of the campuses of the renowned International School of Geneva, Swiss health authorities said on Thursday.

The first round of the COP15 gathering was held in October in southwest China's Kunming, though many attended the meeting virtually due to the coronavirus pandemic.

It saw the adoption of a declaration to recognise the importance of biodiversity in human health, strengthen species protection laws and improve the sharing of genetic resources.

After Geneva, delegations were supposed to meet in person in Kunming in late April for a third and last round of talks to hammer out more detailed conservation targets for the next decade.

Elizabeth Maruma Mrema, executive secretary of the UN Convention on Biological Diversity organising the summit, said she hoped it would still move forward when the time was right.

"I am confident that in due course... when it is safe to meet in person again, we will hold these meetings and advance on our journey to Kunming and the successful adoption of the post-2020 global biodiversity framework," she said.

COP15's biodiversity discussions are separate from the weightier COP26 summit held in November towards fighting climate change.