An Australian man has been confirmed as among six people killed after two sightseeing seaplanes crashed midair in Alaska.

Four Americans and one Canadian were also among those killed when two planes carrying 16 people – including the two pilots – collided and plunged into the icy cold waters of a inlet near the south-eastern Alaskan town of Ketchikan on Monday, the US coast guard said.

Four bodies were recovered after the crash on Monday and another two were found by divers on Tuesday, the coast guard said.

Investigators believe one of the planes was descending at around 3,000ft (1,000m) when it collided with the other plane.

Ketchikan is a popular destination for cruise ships in Alaska. Ten other people, all Americans, were injured.

Emergency response crews transport an injured passenger to an ambulance at the George Inlet Lodge docks on Monday. Photograph: Dustin Safranek/AP

A spokesman for the Department of Foreign Affairs confirmed to Seven News that the Australian passenger was among the dead.

The Royal Princess, which can carry up to 3,600 people, was among four city-sized cruise ships in the tiny coastal community on Monday.

During port stops, visitors can opt to take the flightseeing trip in Misty Fjords national monument to see the lakes, snowcapped peaks and glacier valleys in the wilderness area. Trips cost about $260 each.

The larger plane, a de Havilland Otter DHC-3 with 10 passengers and the pilot, was returning from Misty Fjord when it collided with another sightseeing plane, carrying four passengers from the same cruise ship and a pilot.

The Australian man was believed to have been on the smaller plane along with a Canadian, two Americans and an American pilot.

The crash took place about eight miles (13km) from Ketchikan, near George Inlet in relatively good weather although it was overcast. The planes came down about a mile-and-a-half (2.5km) apart with some of the debris field on land.

A coast guard helicopter searches for survivors near Ketchikan. Photograph: HANDOUT/Reuters

Federal accident investigators called in to help with the investigation told Associated Press that the larger plane was descending when it collided with the other aircraft.

National Transportation Safety Board spokesman Peter Knudson said the Otter had descended to an altitude of 3,200 to 3,300 feet (over 1,000m) when it collided with the smaller Beaver plane as both headed back to Ketchikan. Knudson says the Beaver had been flying at a 3,300-foot altitude.

The Beaver was found partially submerged in the shore of George Inlet after the single-engine plane overturned and hit some trees before crashing, according to coast guard Lt Brian Dykens. The larger Otter landed in water and sank, he said.

Canadian officials said Tuesday that one of its citizens was among the dead. Global Affairs Canada expressed condolences but did not identify the person because of privacy reasons.

The smaller plane, which operated independently and not as an official excursion flight booked through the cruise ship, was owned by Mountain Air Service of Ketchikan, which didn’t immediately return a call Tuesday.

The Beaver appears to have broken apart in midair, according to Jerry Kiffer, duty incident commander of the Ketchikan volunteer rescue squad. He said the plane’s tail and section of the fuselage were 900 feet (275m) from the aircraft’s floats, which landed near shore.

After the crash, the 10 injured passengers were initially taken to a hospital in Ketchikan. Four patients were later transferred to Harborview medical center in Seattle, suffering various broken bones, spokeswoman Susan Gregg said.

Last summer, all 11 on board another Taquan Air flight survived when the 72-year-old pilot confused snow on a mountain with a body of water and crashed on a rocky mountainside on Prince of Wales Island near the southern tip of the Alaska Peninsula.

A pilot and eight cruise ship passengers died 25 June 2015 when a de Havilland DHC-3 Otter operated by Promech Air Inc crashed into mountainous terrain about 24 miles (38km) from Ketchikan, also as it was returning from Misty Fjords.

The Royal Princess left Vancouver, British Columbia, on 11 May and was scheduled to arrive in Anchorage on Saturday.

“We are extending our full support to the investigating authorities as well as the travelling companions of the guests involved,” the company said in a statement.

A DHC-2 Beaver seaplane crashed on 31 December 2017 in the Hawkesbury River near Sydney, Australia, killing five British tourists and the pilot.