Authorities in Indonesia have tightened border curbs, extended quarantine and limited movement on strategic toll roads, in a preemptive move to limit the spread of the Omicron Covid-19 variant should it reach Southeast Asia's biggest country, Reuters reports.

Indonesia, once Asia's coronavirus epicentre, has yet to announce the detection of Omicron, but is stepping up measures to minimise the potential impact, including extending the mandatory quarantine for arrival from seven days to 10.

Travel to Indonesia from 11 countries, including South Africa, Botswana, Namibia and Nigeria, will not be allowed, except for returning Indonesians, who will be subjected to 14 days of isolation.