Oxfam have expressed fears over the spread of coronavirus in refugee camps, with up to 250 people sharing one tap in some places that are already struggling for food.
The charity says the virus could also be catastrophic for people in places hit by conflicts, such as Yemen, Syria and South Sudan.
Marta Valdes Garcia, Oxfam coronavirus response operations lead, warned millions of people are already suffering chronic and severe food shortages.
The rsie of Covid-19 and any restrictions needed to help deal with it she said are also “likely to further compromise their food security as well as their jobs and livelihoods”.
Ms Garcia said: “The death toll around the world is rising rapidly but this will be just the tip of the iceberg if and when the virus spreads to the world’s most vulnerable communities.
“Camps for people who have been forced to flee their homes are simply not set up to cope with a pandemic like coronavirus.
“Aid agencies will need to work even harder to prepare for and deal with the arrival of this disease.
“While many nations are understandably focused on containing the spread of the pandemic amongst their own population, it’s crucial they don’t turn their back on millions of the most vulnerable people worldwide.
“The international community needs to mobilise huge resources behind developing countries to cope if we’re to honour the promise of ‘no-one is safe until we’re all safe’.”
In the case of the Rohingya refugee camp at Cox’s Bazar in Bangladesh, there are 40,000 people per square kilometre despite the standards stating there should be one tap for no more than 250 people and 3.5 square metres of living space per person.
Elsewhere, the Moria camp on the Greek island of Lesbos was built for 3,000 people but now hosts nearly 20,000 people.
Up to 160 people use the same toilet and there are more than 500 people per shower.
In some parts of the camp, 325 people share one tap without soap, while 15 to 20 people can be living in a single shipping container.
While the standards for camps are agreed by agencies responding to humanitarian crises, Jamie Livingstone, head of the charity in Scotland, suggests they cannot cope with a global pandemic.
Basic preventive measures like staying at home or washing hands more frequently are simply impossible
Mr Livingstone said: “Our lives and livelihoods have been severely affected by coronavirus as we all restrict our behaviour to help stop its spread.
“Coronavirus is an unprecedented threat to those living in poverty, and those who risk being dragged into it because of its impact on people’s incomes.
“It’s hard to look beyond our own walls when for many people it may feel like they’re closing in around us. But it’s clear that the virus doesn’t respect town, city, region or national borders.
“For many of the world’s most vulnerable, basic preventive measures like staying at home or washing hands more frequently are simply impossible.
“We also know that women are hit hardest by emergencies, and women carry the bulk of caring responsibilities, making them even more vulnerable to exposure to this virus.
“As we together come to terms with the terrible and devastating impact, we must also turn our attention to the action needed to protect the people facing heightened risk and those who are least able to cope in this global pandemic.”
A UK Government spokesman said: “The UK is providing £544 million to the global fight against coronavirus which includes the largest single contribution of any country to the international fund to develop a coronavirus vaccine.
“We are strengthening fragile healthcare systems in the world’s poorest countries to help them cope with the outbreak and are helping to prevent the spread of diseases in refugee camps around the world by providing access to clean water and sanitation.”