26/06/2017 9:03 AM AEST | Updated 26/06/2017 3:58 PM AEST

Ferry Packed With 170 Tourists Sinks In Colombia

Nine people have been confirmed dead and at least 28 still missing.

Nine people have been confirmed dead and at least 28 missing after a crowded ferry carrying up to 170 tourists sunk on a reservoir in north-west Colombia.

A major rescue operation was launched on Monday (AEST) including Colombian Air Force helicopters helping to evacuate tourists, while firefighters and scuba divers were also sent to the tourist town of Guatapé, where the shipwreck occurred.

Footage posted on social media shows the three-level boat swaying precariously from side to side as it sinks into the the Peñol-Guatapé Reservoir near the tourist town, 45km east of Colombia's second largest city of Medellin.

Numerous recreational boats rushed to the scene to pick up tourists, many of whom climbed down from the top deck and jumped into the water.

The reasons why the boat sunk remain unclear but survivors said the boat, called El Almirante, appeared to have been overloaded and none of the passengers on board were wearing life vests, according to Associated Press.

Earlier, Colombia National Police's Director General, Jorge Nieto, said on local station Blu Radio that at least three people were dead and authorities were in the process of identifying the bodies.

Colombia's President Juan Manuel Santos has confirmed the incident, tweeting that the air force and relief agencies had been called in.

"We are ready to provide the required assistance," he said in Spanish.

The Colombian Air Force confirmed that helicopters were evacuating the most seriously injured people, posting a photo to social media showing rescue operations underway.