The parents of the surviving Bali Nine members are “quietly hopeful” their children will be repatriated to Australia in a deal with the Indonesian government, according to a pastor who has been in close contact with them for 20 years.

The prime minister, Anthony Albanese, raised their repatriation during a meeting with the Indonesian president, Prabowo Subianto, on the sidelines of the Apec summit in Peru last week. Senior Australian ministers have confirmed negotiations between the two nations are ongoing.

Indonesia’s law minister, Supratman Andi Agtas, has also confirmed the president’s in-principle support for the extradition. He said the delay in officially announcing a deal was due to the two nations not having a prisoner swap arrangement.

When asked by Guardian Australia if the remaining members of the Bali Nine could be home by the end of the year, the minister said: “Hopefully, but it will depend on the president.”

“It’s based on humanitarian grounds and also about good relations between Australia and Indonesia,” he said.

Supratman confirmed any deal with Australia would involve some Indonesian prisoners in Australia being returned. He said his department was working to create the legal mechanisms required to exchange prisoners.

He said that “in principle we want to do it” and that “it’s in process”.

Supratman also confirmed he had discussed the issue with Australia’s ambassador in Jakarta, Penny Williams, in recent days.

The Australians were arrested in 2005 for attempting to smuggle heroin out of the Indonesian resort island. The remaining members, who remain in Bali serving life sentences, are Scott Rush, Matthew Norman, Si-Yi Chen, Martin Stephens, and Michael Czugaj.

The bishop of Townsville, Timothy Harris, has provided pastoral care to the Rush and Czugaj families since their arrest. He has also visited both men in Bali’s notorious Kerebokan prison.

“It is fantastic news, if true,” Harris said. “But I am being very cautious.

“I am very grateful for conversations that have taken place between the Australian prime minister and the president of Indonesia. I think those two men need to be congratulated and credit given where it is due.”

Harris said he has spoke with Rush’s father, Lee, in recent days and he believed the family has not yet received any official confirmation of a deal. He was wary of hard-line Indonesian politicians seeking to stop the repatriation.

“Scott’s parents are salt-of-the-earth people,” Harris said. “They have been through hell and I think they are quietly hopeful they will get their son home.”

“After 20 years, how much more can a person take? There comes a time where it is better to bring them home.”

Harris stressed that he and the Rush family wanted the Indonesian justice system to be respected.

On Sunday, the trade minister, Don Farrell, said the five men would continue to serve their sentences in Australia if the deal went through.

“The proposal isn’t, as I understand it, to release these people,” he told Sky News. “They would continue to serve their sentence, except they’re serving them in Australia.”

The shadow attorney general, Michaelia Cash, said the prime minister should provide Australians with more information about the deal. She did not say whether the opposition backed the reported deal.

“Let’s be clear, in the first instance, these individuals … were part of a heroin-smuggling ring to bring back into Australia in excess of 8kg of heroin,” she told Sky News on Sunday.

“Drug offences are some of the worst offences our society sees because of the devastating consequences on people, including death.”