The family of a hiker lost for four days in dense bushland are on their way to north Queensland to join the search.
Juliana Castrillon, 38, was last seen hiking away from Cedar Bay towards Home Rule in the Ngalba Bulal National Park, south of Cooktown, on Saturday morning after attending the Orin-Aya music festival.
Home Rule is part of the Northwest Tropics World Heritage Area and features extensive rainforests and waterfalls.
Ms Castrillon set off without water or supplies on the 14-kilometre track.
"It's classified as a strenuous activity with some extremely difficult terrain once you get off the walking track," Inspector David Perry told reporters.
"It's suggested you allow eight hours to do that walk."
The ground search was launched after a two-day aerial search failed to find any trace of the Columbian national.
Insp Perry said the missing hiker would have access to water and the chances of survival were high.
"It's more like the wildlife ... whether it be venomous snakes that are in the area, crocodiles that might be in the area," he said.
"There are some quite deep ravines and dangerous waterways in the area as well, so they are all areas of concern in relation to survivability."
Insp Perry said Ms Castrillon's family had been informed of the search progress and were on their way to the area.
"She's Colombian but she resides in Australia and she actually is, from my understanding, a business owner in New South Wales and she's got family residing in Australia.
"They're actually either on their way, or they're already here."
Ms Castrillon is 169 centimetres tall with black hair and brown eyes. Police have urged anyone with information about her whereabouts to contact them.