The World Health Organization on Wednesday said international travel bans "do not provide added value and continue to contribute to the economic and social stress" of countries.
In a statement issued after a WHO meeting, the UN health agency said travel restrictions that were introduced to curb the spread of the omicron variant of the coronavirus demonstrated "the ineffectiveness of such measures over time."
In late November, several countries suspended flights to and from southern African countries, citing concerns over omicron. Most governments have lifted this ban.
The WHO also urged countries not to require proof of vaccination against COVID-19 as the only way for travelers' entry, citing inequity in vaccine distribution.
Countries should consider adjusting some measures, including testing and quarantine requirements, "when appropriate," that put a financial burden on travelers, the WHO said.
Separately, the WHO said that coronavirus cases globally rose by 20% last week to more than 18 million.
Infections increased in every world region except for Africa, where cases fell by nearly a third, according to the WHO.
The number of deaths globally remained similar to the previous week, at about 45,000.