“A cruise ship arriving in Vietnam provides an average of nearly 100 guests who book tours to Cambodia and then return to Vietnam to continue their voyage,” Tuan said.

Because it takes only an hour to fly to Siem Reap from HCMC, tourists can return the next day instead of going on a trip to provinces in the Mekong Delta, which takes hours by bus.

One-day tours to Siem Reap from HCMC would attract more cruise ship guests if more evening flights opened, Tuan said.

The third highest group of foreign visitors to Angkor Wat, Japanese tourists, is increasingly choosing Vietnam as the next destination after Cambodia, according to figures released by the APEX Cambodia Travel Service Company.

The number of Cambodian tourists to Vietnam for sightseeing, shopping and medical check-ups and treatments is also on the rise.

Cambodia has shifted many tours from Thailand to Vietnam because of the opening of many border gates between the two countries, medical travel and similarities between food and beverages between the two countries, according to He So Somara, Secretary of state of the Cambodian Ministry of Tourism.

With many international airports and international air routes to Vietnam, foreign visitors can travel to Vietnam and then fly or travel by road or waterways to Cambodia and return to Vietnam to head home.

According to the Vietnam National Administration of Tourism, the number of Cambodian tourists traveling to Vietnam soared by 147.2% in the first quarter of the year against the same period last year.

The seat occupancy of five flights from Vietnam to Cambodia every day reached 80 to 95% in March, a representative of Vietnam Airlines said.

The HCM City-based Medic Medical Centre has in recent months received more than 100 patients from Cambodia for health check-ups and treatments every day, accounting for 10% of the total number of patients registering at the centre, according to Dr Phan Thanh Hai, director of the centre.

Pham Quang Hung, Director of the Department of International Cooperation under the Vietnam National Administration of Tourism, said that tourism authorities of Cambodia, Laos and Vietnam would jointly organise promotion programmes to tap potential markets during the International Travel Expo, which is scheduled to open in September 30 in HCMC.

A proposal for a single visa for Cambodia, Laos and Vietnam is being considered and will be submitted to the Government, Hung said.