The blood-sucking bugs carry a number of potentially lethal diseases, including dengue fever, West Nile virus and Zika, which can affect unborn babies.
Experts fear a long, hot summer could bring a mosquito explosion not seen for more than a decade.
Tiger mosquitoes are thought to have arrived in Britain in small numbers in 2010.
They are sturdier and fiercer than our native species.
The female is the more aggressive and will attack and bite within seconds of landing on a body.
Swarms of the bugs, which are easily identifiable through their black and white striped legs and the white dash on their head, will emerge over the coming weeks, experts fear.
Numbers have grown since 2016, partly due to holidaymakers and cargo lorries unwittingly bringing them back on journeys across the English Channel.
The insects find ponds and pools of stagnant water, where they lay their eggs.
These lie dormant over winter before hatching, with the bugs taking to the air in the spring.
Public Health England (PHE) confirmed tiger mosquito eggs have been identified at sites in Kent, south-east England.
Although there have been sightings in parts of southern England over the past eight years, PHE only confirmed their presence in 2016.
The British Pest Control Association (BPCA) said that wet weather coupled with a rise in spring temperatures provides a fertile environment for insects such as mosquitoes to flourish.
Dee Ward-Thompson, BPCA technical manager, said: “The public can take steps to reduce the opportunities for mosquitoes in general to take hold.
“Simple corrective measures include removing still, standing water from areas such as blocked guttering, wheelbarrows and birdbaths.
“Water butts can also provide ideal breeding sites for the insects so should be cleaned out regularly.
“Anybody who does come across this insect should contact a professional pest controller and the GB Non-native Species Secretariat.”
Tiger mosquito numbers have soared in France due to the hot weather in early spring.
Eggs, larvae and adult insects can be easily carried over the English Channel, further boosting their numbers in the UK.
The UK is home to more than 30 native mosquito species, some of which bite and create a general nuisance.
The most common species indoors, often misidentified as a gnat, is Culex pipiens. It does not bite but is almost indistinguishable from Culex molestus, which does.
