The FCDO on Tuesday (5 July) warned shortages of certain "basic necessities", such as a fuel, medicines and food, were becoming increasingly acute. The advice doesn’t apply to airside transit through Sri Lanka’s Bandaranaike International airport.
It comes just under a month after the FCDO relaxed its Sri Lanka travel advice. It initially advised against all but essential travel to the country on 13 May.
This followed several weeks of unrest in the country, which led to prime minister Mahinda Rajapaksa resigning on 9 May following a mass cabinet resignation.
Tui cancelled all Sri Lanka departures through to the end of June, while specialists told TTG they were hopeful the situation in the country would stabilise in July.
"Sri Lanka is experiencing a severe economic crisis which has led to shortages of basic necessities including medicines, cooking gas, fuel and food," said the FCDO on Tuesday.
"There is a major shortage of fuel [diesel and petrol] affecting transport, businesses and emergency services. There are daily power cuts due to electricity rationing. This has led to protests and violent unrest.
"Further protests, demonstrations, roadblocks and violent unrest could occur at short notice."
The Sri Lanka Tourism Development Authority has partnered with the country’s ministry of tourism to provide emergency assistance for "commuting and arriving guests", such as fuel.
The FCDO is advising travellers to ensure they plan any journeys well in advance and have contingency plans should their journey be disrupted, adding that if they are travelling to and from the airport, they should check their flight status in advance and allow extra time.
Previously, international travellers have been able to use evidence of a valid journey, such as a flight ticket, to get an exemption from curfew rules.
