The law, which aims to help protect endangered animals and has the backing of celebrities including model Kate Moss and football presenter Gary Lineker, is to be voted by British lawmakers on Friday.
But many communities and government officials across southern Africa are against the ban.
"What the UK is doing is imposing their very urban, sanitized thinking on us," said Chris Brown, the head of Namibian Chamber of Environment (NCE).
Trophy hunting - where hunters pay sometimes thousands of dollars for the right to kill usually big game animals like elephants and lions - has long been controversial.
Critics say shooting wild animals for fun is cruel, wasteful and pushes endangered species closer to extinction.
Hunters often bring home parts of the animals as trophies, like skulls, skins, tusks or claws.
"Can anyone tell me a better definition of colonialism than white people flying to Africa and saying, 'I'm going to shoot these animals for fun, it's my right to do so'?" Eduardo Goncalves, founder of the Campaign to Ban Trophy Hunting told a meeting in support of the bill in Westminster on Wednesday.
But proponents contend that the killing of a small number of selected animals generates much needed income to boost conservation efforts and support local communities.
- 'Re-colonising Africa' -
In a letter to Britain's Minister for Development and Africa, Andrew Mitchell earlier this month, dozens of conservationists and community leaders from Botswana, Angola, Zambia and Namibia warned the law would have a negative impact.
"With reduced revenue from trophy hunting, poaching will increase because there will be less funding to pay salaries to the community game guards," the letter read.
"We feel as if this is another way of re-colonizing Africa."
Thato Raphaka, a permanent secretary at Botswana's Ministry of Tourism and Environment, said southern African countries have been lobbying for the law to be dropped.
Botswana, which boasts the world's largest elephant population of around 130,000 tuskers, banned trophy hunting in 2014 but lifted the restriction five years later, following pressure from local communities.
Ex-president Ian Khama, an avid environmentalist, remains one of few voices in the region opposing game hunting.
"Hunting... is not sustainable especially if poaching is not under control," he told AFP.
It "only adds to the decline" in wildlife, he said.
- Wildlife numbers crashing -
Wildlife numbers in Africa have dropped 66 percent since 1970 according to the World Wildlife Fund.
Yet the group said that when well-managed, trophy hunting has proven to be an "effective conservation tool".
Brown, an environmental scientist, said local communities had a much better idea of how best to protect wildlife than lawmakers sitting thousands of miles away in London.
He pointed to a 2017 study ranking countries' efforts to protect big animals like rhinos and bears.
Namibia and Botswana came out top, while Britain was rated "below average" at number 123 on the list.
In Namibia trophy hunting affected about one percent of the total wildlife every year and mostly occurred on private farmland, not in national parks.
Were it to be banned, farmers would lose an incentive to live alongside disruptive animals such as lions, cheetah, hyenas, elephants and crocodiles, said Brown, who is vegetarian.
Rhino numbers in the country have more than doubled since 2005 despite a constant threat from poachers, according to the International Rhino Foundation.
Britons make up a small share of trophy hunters in southern Africa.
Most hunters in South Africa come from the United States, according to a 2021 report by animal rights group Humane Society International, with the UK not even appearing in the top 10 of the list.
But Brown said were the British law to pass, there were fears other countries would follow.
"People think they're doing the right thing for conservation, but they're actually undermining it," he said.
JOHANNESBURG - A bid to ban the import of hunting trophies to Britain has upset conservationists in southern Africa, with some saying the bill is counterproductive and smacks of colonialism.