The coronavirus crisis could cost global tourism and related sectors at least 1.2 trillion U.S. dollars, the United Nations (UN) said Wednesday.

Prevailing lockdown measures in some countries, travel restrictions, reductions in consumers' disposable income and low confidence levels could significantly slow down tourism's recovery, said the UN Conference on Trade and Development (UNCTAD) in a report.

The UN's trade and development body expects that the sector could lose 1.2 trillion U.S. dollars, or 1.5 percent of the global gross domestic product (GDP), in the best-case scenario. If the break in international tourism lasts for 12 months, the loss could climb to 3.3 trillion U.S. dollars or 4.2 percent of the world's GDP, UNCTAD warned.

The tourism hit can be seen as a reminder of economic loss for millions of people all around the world, said UNCTAD's director of international trade, Pamela Coke-Hamilton.

"For many countries, like the small island developing states, a collapse in tourism means a collapse in their development prospects. This is not something we can afford," she added.

She clarified that developing countries could suffer the steepest GDP losses.

"Jamaica and Thailand stand out, losing 11 percent and nine percent of GDP, respectively, in the most optimistic scenario of UNCTAD's estimates," noted the director.

UNCTAD also believes the tourism recession would slashed some countries' national incomes. It estimates that for every one million U.S. dollars lost in international tourism revenue, a country's national income could decline by two million to three million U.S. dollars.