UK scientists have reached a milestone in the fight against malaria by creating a genetically modified mosquito that is infertile, reports said.

The plan is to wipe out the insects that spread malaria to people via bites, Nature Biotechnology reported.

Scientists said two copies of the mutant gene render the malaria-carrying female insect completely barren. But one copy is enough for a mosquito mum or dad to pass it on to the offspring.

This should perpetually spread the infertility gene throughout the population so the species dwindles or dies out, the experts said.

However, the Imperial College London team said more safety tests were needed, meaning it will be a decade before the mutant mosquitoes can be released into the wild.

The mutant mosquito can still carry and transmit malaria to people via bites. But, according to scientists, their genetic make-up means they should breed with and replace other malaria-carrying mosquitoes.

Any offspring with one copy of the gene would carry on passing the trait to future generations, while any female offspring that inherits both copies would be unable to reproduce, reports added.

But Prof Tony Nolan said their method should not make a big dent in the overall mosquito population - just the ones that transmit malaria.

"There are roughly 3,400 different species of mosquitoes worldwide and, while Anopheles gambiae is an important carrier of malaria, it is only one of around 800 species of mosquito in Africa, so suppressing it in certain areas should not significantly impact the local ecosystem," he said.

David Conway, an expert in malaria at the London School of Hygiene and Tropical Medicine, said the work held promise.

"The key achievement here is that a novel genetic drive mechanism can force these modifications to be passed on, using a trick that would not occur in nature," Prof Conway said.

But he said more work was needed to check that the mosquitoes do not evolve resistance to the genetic modification.

Malaria is responsible for nearly half a million deaths a year. The World Health Organisation reported a huge fall in the number of cases of malaria in September. WHO said in Africa, around 700 million cases have been prevented since 2000.