The area around Victoria Falls has a large concentration of elephants
Noise pollution from helicopter flights over Victoria Falls could badly affect important elephant herds in Zimbabwe, environmentalists have warned.
They say senior government ministers are backing plans for a four-fold increase in tourist flights.
It is part of attempts to take advantage of an expected tourist boom when neighbouring South Africa hosts next year's football World Cup.
Work has already begun on new helipads but without official permission.
Zimbabwean Environment Minister Francis Nehema says no environmental impact assessment has been made - and without it the scheme cannot go ahead.
"It doesn't matter who you are. We want it done. It is a prerequisite," he said.
Zimbabwean journalist Brian Hungwe says at present just five helicopters fly over the falls at any one time.
That figure is set to grow to around 20, as tourists scramble to secure stunning aerial views of one of the world's most spectacular sights, he says.
But environmentalists fear excessive noise pollution will have an adverse effect on the behaviour patterns of the elephants.
And Deliwe Utete from non-governmental organisation Environment Africa says if the elephants flee it could have worrying repercussions for the resort's entire ecosystem, affecting thousands of wild animals and birds.