The divers, who were named 2019 Australians of the Year, have written to the Thai prime minister to free the refugee

The Thailand cave rescue diving heroes and Australians of the Year, Dr Richard Harris and Dr Craig Challen, have joined the campaign to save the refugee footballer Hakeem-al Arabi, a Bahraini refugee and resident of Australia who is being detained in Bangkok.

Harris, an anaesthetist and diver from Adelaide, and Challen, a champion diver from Wangara, Western Australia, were part of the global team that freed the trapped Wild Boars football team in July 2018. They have been friends and cave diving partners for years.

The men, who stayed in the underwater Tham Luang cave system for three days, swimming multiple kilometres in hazardous conditions, have written to the prime minister of Thailand, with the support of the foreign affairs department, to release Al-Araibi from jail.

Facebook Twitter Pinterest Richard Harris (left) and Craig Challen at the 2019 Australian of the Year awards in Canberra last month. Photograph: Mick Tsikas/EPA

According to the ABC, a letter was sent a few days ago to the Thai prime minister, Prayut Chan-o-cha, asking him to consider freeing Al-Arabi, who is waiting for an extradition hearing to be taken back to Bahrain, which is seeking his extradition for a 10-year jail sentence which al-Araibi claims is politically motivated.

The Melbourne-based footballer was detained on 27 November by the Thai authorities when he arrived in Bangkok for his honeymoon.

Australia has demanded his release and return. He was formally granted refugee status in 2017.

Play Video 0:39 Refugee footballer Hakeem al-Araibi arrives at court in Thailand – video

On Saturday, foreign affairs minister Marise Payne wouldn’t tell reporters the contents of the letter Harris and Challen had sent.

Instead she said the government had “engaged at the highest level” with the Thai government to ensure that Al-Araibi was returned to his home in Melbourne “as soon as possible”.

“I did that myself when I was in Bangkok last month,” she said. “Obviously there are legal proceedings underway and we are monitoring those.

“We’re providing the necessary assistance to Mr Al-Araibi’s defence lawyer to ensure that he does have the best chance of returning home and I remain in close touch with our post in Bangkok on that.”

On Tuesday, the Australian prime minister, Scott Morrison, had said seeing Al-Araibi in shackles had prompted him to write to his Thai counterpart for the second time, after first writing last week to call for Al-Araibi to be sent back to Australia.

“I’ve written to him again, because I was very disturbed at the appearance of Hakeem at the hearing the other day,” Morrison had told Sky News. “He was shackled and I thought that was very upsetting and I know it would have upset many Australians.

“I’m respectfully reminding the Thai prime minister that Australians feel very strongly about this, very very strongly.”

The images, which were broadcast internationally, have also upset Thai people. Thai media is not permitted to show prisoners in restraints and local outlets including the Bangkok Post airbrushed the shackles out of pictures.