Rescue teams today launched an aerial search for a missing British tourist who is feared to have drowned in Bali.

Harrison Edward Nada Kontounas, 23, allegedly ignored red warning flags to go swimming with two friends at Legian Beach on Wednesday afternoon.

Coast Guard officers warned the trio to leave the marked zone, where the waters were dangerous due to sudden rip currents, but Harrison was reportedly dragged out to sea after being struck by a large wave.

A search of the coastline was carried out by boat on Wednesday evening followed by helicopters on Thursday afternoon. Jet skis and thermal drones are also being used.

Officials said that if Harrison, from Ilford, East London, is not found by Friday they will plan a different approach.

Speaking today, Nyoman Sidakarya, Head of the Denpasar Search and Rescue Office, said: 'The conditions at this time of the year are challenging. Tourists should not swim in the sea.

'The search will continue today by air and sea. The Bell 407 GXP helicopter took off at 12:15pm, with one pilot and two rescuers onboard. Further Coast Guard vessels searched the coast and all boats in the area have received details of the missing person.

'Aerial monitoring is being conducted with a thermal drone, and ground SRUs are patrolling the surrounding beach areas.'

The Denpasar Search and Rescue Office (Basarnas) said wind speeds of up to 39 kph had been blowing through the beach at the time Harrison was dragged out to sea.

Rescue teams scoured along the coastline, but were unable to deploy search equipment in the water. The effort was conducted until 10 pm local time on Wednesday but Harrison remained missing.

Nyoman Sidakarya, head of Denpasar Basarnas, added: 'We received a report at 6:40 pm about a drowned foreign national from Mr. Ipel, Balawiata Kuta, and five personnel were dispatched to the location.

'Our initial step is to coordinate with witnesses and other SAR elements. If nothing is found tomorrow morning, we can determine our next action plan.

'Winds above 30 to 39 km/h can be considered strong, and this will affect conditions in the waters. Therefore, caution is advised when engaging in outdoor activities, including beach tourism.'

Harrison, from Ilford, East London, is a management trainee at London-based construction company Arc Group. He was with two friends who made it out of the sea when he disappeared off the tropical Indonesian island.

Legian Beach is located next to Kuta Beach, which is notorious for its strong rip currents and powerful waves that have led to numerous drowning incidents over the years, usually involving tourists and inexperienced swimmers.

Lifeguards patrol the area and put up warning flags but accidents still occur during the high tide or when beachgoers swim outside designated safe zones.