Cave diving heroes and joint Australian of the Year recipients Richard Harris and Craig Challen have joined efforts to free Melbourne-based refugee footballer Hakeem al-Araibi from a Thai prison.

Key points: A number of high-profile people have joined the bid to get Hakeem al-Araibi freed from a Bangkok prison

A number of high-profile people have joined the bid to get Hakeem al-Araibi freed from a Bangkok prison Craig Challen and Richard Harris recently helped save a Thai junior football team from a flooded cave in northern Thailand

Craig Challen and Richard Harris recently helped save a Thai junior football team from a flooded cave in northern Thailand Mr al-Araibi has spent two months in prison and will remain in custody until his next court hearing in late April

The two dive experts, who saved the 12 Thai footballers and their coach from a flooded cave last year, have added their names to the campaign to release Mr al-Araibi and stop extradition proceedings brought by Bahrain.

They have written a letter to Thailand's Prime Minister Prayut Chan-o-cha, who has insisted he will not stop legal proceedings to extradite Mr al-Araibi.

The ABC understands the letter was sent days ago.

The 25-year-old faces a 10-year prison term for allegedly vandalising a police station if he is returned to Bahrain.

Thai cave divers Richard Harris and Craig Challen are supporting Mr al-Aribi's bid for release. ( ABC News: Tamara Penniket )

He was detained in Thailand in December when he and his wife arrived for their honeymoon and strongly denies the charges, which he said were politically motivated.

In jail with a playing deal and plenty of support

Despite being kept in custody as he waits for his next court hearing in April, Mr al-Araibi has embarked on a training routine behind bars — doing push-ups and running without shoes.

He has refused to give up on his football career at Pascoe Vale, even though there are grave fears he could be forcibly returned to his homeland and may never return to Australia.

The Melbourne club said it had already signed Mr al-Araibi for the 2019 season and his team shirt was ready.

Mr al-Araibi will remain in custody until his next court date in April. ( Reuters: Athit Perawongmetha )

Prime Minister Scott Morrison has repeatedly called for Mr al-Araibi to be freed, along with several high-profile footballers like Gary Lineker, Robbie Fowler and Didier Drogba and former Socceroos captain Craig Foster.

Mr Foster said he hoped to meet Mr Morrison in person next week to discuss further measures, and also planned to visit Geneva to meet representatives from the United Nations.

The Thai Attorney-General's office (OAG) has defended the extradition process, and repeated claims that the Thai Government lacked the power to stop the case.

It has also warned that Mr al-Araibi could remain in jail until August, while the Criminal Court assesses Bahrain's extradition request.