Five men have been caught crossing illegally into Australia on a small dinghy in Far North Queensland.

The men — reportedly from the West African nation of Senegal — are in custody on Saibai Island in the Torres Strait, about 4 kilometres from the Papua New Guinean mainland.

PNG Police Commissioner David Manning said they travelled to Papua New Guinea via Indonesia, using fake travel documents, before they attempted to cross into north Queensland.

Two PNG nationals are being questioned over their alleged involvement in trafficking the five men to Australia by boat.

"It's an ongoing investigation," Commissioner Manning told the ABC.

The Australian Border Force (ABF) declined to comment on specifics but a spokesperson told the ABC it had "well-established processes to manage irregular movements of people in the Torres Strait".

Daru Mayor Samuel Winggu said he was aware authorities were searching for the Senegalese men in PNG's South Fly region last week.

PNG Assistant Police Commissioner Hodges Ette told Post Courier the group was caught in mangroves on Saibai Island while trying to run from ABF officials.

The ABC understands the men are in ABF custody on Saibai Island and are undergoing health checks.

Australia shares a sea border with Papua New Guinea in the Torres Strait but illegal crossings by foreign nationals are uncommon.

In 2017, a boat carrying six Chinese nationals landed on Saibai Island.

A unique treaty set up to recognise traditional relationships between PNG and the Torres Strait allows visa-free travel for locals from villages and islands in the region.

The treaty was suspended in 2020 due to COVID-19 concerns. However, it has now resumed with restrictions on the days and times people can travel across the border.