The problem of snake bites, which kill tens of thousands of people each year, is being exacerbated by climate-induced flooding in a number of countries with little access to antivenoms, the WHO warned Tuesday.

Each year, as many as 2.7 million people are bitten by poisonous snakes, with up to an estimated 138,000 deaths.

"One person dies from snake bite every four to six minutes," David Williams, a World Health Organization snakebit expert, told reporters in Geneva.

Far more people -- around 240,000 each year -- are left with permanent disabilities, he said.

Snake venom can cause paralysis that stops breathing, bleeding disorders that can lead to fatal haemorrhage, irreversible kidney failure and tissue damage that can cause permanent disability and limb loss.

Most snake bite victims live in the world's tropical and poorest regions, and children are worse affected due to their smaller body size.

Williams stressed that disabilities caused by snake bites can drive not only the victims but their entire family into poverty due in part to the high cost of treatment, but also loss of income when the family breadwinner is the victim.

A major problem, he warned, was that "some regions of the world simply don't have enough safe and effective treatments available to them".

Sub-Saharan Africa, for instance, has access to just around 2.5 per cent of the treatments it is estimated to need.

The UN health agency explained in 2019 that production of life-saving antivenoms had been abandoned by a number of companies since the 1980s, sparking a grave shortage in Africa and some Asian countries.

India is the worst affected country in the world, with around 58,000 people dying there due to snake bites every year, while its neighbours Bangladesh and Pakistan are also hard hit, Williams said.

The impacts of climate change are meanwhile worsening the situation in some places, he said, pointing in particular to how flooding can often increase the number of snakebites.

He pointed to Nigeria, which is currently "going through a critical shortage of snake antivenom due to an influx of additional cases of snakebite that have been brought about by the flooding".

"And this is a problem that occurs in many areas of the world where these sorts of disasters occur on a regular basis," he said.

Major flooding events in Pakistan, Myanmar, Bangladesh, South Sudan and other countries had also been followed by a rise in snakebites.

WHO also warned that climate change risked shifting the distribution and abundance of venomous snakes, possibly exposing previously unaffected countries to the dangers.