Charred bodies found in a burnt-out campervan in Mexico are those of two Australian surfers missing since last month, DNA testing has confirmed.

Perth friends Dean Lucas and Adam Coleman had driven to Mexico from Canada for a surfing tour and were due to arrive in the city of Guadalajara to visit Mr Coleman’s girlfriend Andrea Gomez on November 21 but did not arrive.

Grave fears were held for them after their old Chevy van was found gutted on a dirt road in a rural area of Sinaloa, a state plagued by drug wars and home to the cartel of the same name.

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The discovery was about 200km south of where the men were last seen and 716km north of Guadalajara, and it is unclear why they strayed off course.

State attorney general Marco Antonio Higuera confirmed through a spokesman on Monday (local time) the remains were those of the missing 33-year-old men.

Prosecutors believe Mr Coleman was shot in the face after he resisted bandits dressed in police uniforms who had staked out an area of the Benito Juarez Highway.

It is believed the badly injured Mr Coleman and the terrified Mr Lucas were not handcuffed or restrained as they were then allegedly driven off the highway in the darkness of night to a dirt road where they were shot dead before being torched in the van.

Three men – Julio Cesar Muniz, Martin Rogelio Muniz and Sergio Simon Benitez – have been arrested over the deaths, but two suspects remain at large.

Mr Coleman’s family and friends plan to remember the men at a riverside gathering in Perth this weekend.

Surfers from around the world recently commemorated the pair off the coast of Sinaloa and near Perth’s Trigg beach.

Ms Gomez and Mr Lucas’ partner Josie Cox met in Mexico and took to the waves themselves in a tribute to the men.