A South Korean aviation start-up has launched a helicopter taxi service, offering a route from Seoul's Gangnam district to the airport that it says cuts travel time from nearly two hours to 20 minutes.

At a pricey 440,000 won ($320) one-way, the "Vonaer" service will operate once an hour, the company behind it told AFP, for a six-month test period.

"Small air transportation businesses have not taken off in South Korea and because of this urban air services are unfamiliar to the public and related infrastructure is lacking," said Shin Min, CEO of the start up Moviation.

The company will also offer charter services nationwide, with a one way trip from Seoul to southern Busan costing 18 million won ($13,000).

Shin said the company's helicopters were safe and pilots very experienced, adding that the routes would be suspended for severe weather conditions, which could be around 30 percent of the year.

Other South Korean companies are also eyeing the aviation taxi market, or urban air mobility (UAM).

South Korea's biggest telecoms provider, SK Telecom, showcased an air taxi last year developed with Californian start-up Joby Aviation, which it hopes will help cheaply solve congestion in South Korea's cities.

Halfway between a helicopter and a drone, the craft has six electric motors that allow vertical take-offs and landings.

"SK Telecom has developed its own AI-technology-based UAM traffic management system for successful UAM commercialisation," Lee Seok-keon, SK Telecom's UAM business team leader, told AFP.

The company is planning its air taxi demonstration later this year.