Family and friends of Australian yacht skipper Christopher Packer, detained in Bali on suspicion of possessing illegal firearms, say he is in good spirits.

Long time family friend Paul Downie said the South African-born yachtsman's legal team was working with Indonesian authorities to secure his release.

Indonesian coastguard officers found four automatic rifles, a pistol and thousands of rounds of ammunition in Mr Packer's Cook Islands-registered vessel Lissa Avatui off Bali on Friday.

"He is presently being detained at the Benoa Harbour police station, he is working with a legal team, he has very good legal representation," Mr Downie said.

"The legal team are working closely with Indonesian authorities and the police to try to work through the details of what this issue actually is."

But he said Mr Packer was concerned that, if he was charged with possessing illegal firearms, under Indonesian law he could face a maximum penalty of 20 years in prison. He can be held for up to 60 days without charge.

"He's in good spirits ... he is in close contact with his brother [Willy] who is up there and his partner, who is also with him at the moment," Mr Downie said.

Mr Packer, a Perth resident, was detained with four crew members - his Italian girlfriend Gianna Botto, a Spaniard Alvaro Roca, an Indonesian Budi Rachman and a New Zealander Kenneth Brewster, who have all since been released, said Mr Downie.

"He was sailing with several other crew - we are still getting the full details of the crew that were on board with him - [but] the rest of the crew have all been released."

Mr Downie said he could not say why Mr Packer, who had been attacked by pirates on other sailing expeditions, had guns on board, but it was probably to defend the boat against similar attacks.

"We just assumed he kept the guns on board because he was travelling through very pirated waters."

Mr Packer, whom Mr Downie described as an adventurer who had sailed since he was a child, began carrying weapons in 2001 after his Kiwi friend, America's Cup winner Sir Peter Blake, was murdered by pirates in the Amazon River.

"It was really after Sir Peter Blake's death that he decided he should carry firearms, most of the firearms that have been claimed are actually sports rifles," Mr Downie said.

Mr Downie said information was scarce on a Scottish backpacking couple Mr Packer picked up in Broome before sailing to Indonesia.

The male traveller was believed to have been employed as a chef, and his girlfriend was taken on board as a cleaner.

Speaking to journalists as he was taken from his police cell to the boat for a shower on Sunday morning, Mr Packer said the couple had left during a brief layover in Lombok island without saying goodbye.

"Obviously he had a bee in his bonnet about something, but I don't know what it was," Mr Packer said.

"When he left the boat he didn't even say goodbye. Now, looking back on it, it's because he knew he was going to shaft me."

Meanwhile, the Federal Government said on Sunday it was ready to help.

Justice Minister Chris Ellison said Mr Packer's lawyers had contacted the Australian Government, which had offered help.

"Mr Packer's lawyers have been in touch with the Australian Government," he said.

"They are working with the Indonesian authorities, they're assisting them in their inquiries.

"The Australian Government stands ready to assist in whatever way it can to resolve this issue.

"Of course consular assistance is being extended but certainly we want the matter resolved as quickly as possible."

Senator Ellison said the Government realised the matter was within Indonesian jurisdiction but it would keep informed of developments.

"We respect the fact that this is an investigation which is within the jurisdiction of Indonesia but, as I say, Mr Packer's lawyers are in touch with the Government in relation to a number of matters and we are abreast of the situation there," he said.

A Department of Foreign Affairs and Trade (DFAT) spokesman said consular officials had been trying to speak directly with Mr Packer on Sunday.

"Our consular officials have been seeking to meet with him today to offer consular assistance to him directly," he said.

"Our interest is to ensure that he has legal representation and is being treated in accordance with Indonesian law."

AAP