A letter written by a seven-year-old addressed to refugees on Manus Island will be one of many delivered by a group of sailors in a small wooden boat, aiming to bring hope to the people in Australia's offshore detention regime on Papua New Guinea.

Key points: Refugees have been held in offshore processing and transit centres on Manus Island for six years

Refugees have been held in offshore processing and transit centres on Manus Island for six years A group of activists are sailing to PNG to deliver letters and First Nations 'passports' to refugees on Manus Island

A group of activists are sailing to PNG to deliver letters and First Nations 'passports' to refugees on Manus Island A PNG activist says offshore processing and detention has created social tensions

The boat, Lazy Jack, will set sail this week from Cairns, bound for PNG where hundreds of refugees have been held in processing and transit centres since 2013.

The so-called freedom flotilla will deliver 400 symbolic Aboriginal 'passports' as part of Sail 4 Justice.

At the end of the month-long journey to Manus, the sailors plan to give refugees the passports signed by Aboriginal elders and letters of solidarity penned by dozens of Australians.

More than 400 First Nations 'passports' have been signed by Aboriginal elders as a gesture of welcome to refugees on Manus Island. ( ABC Far North: Marian Faa )

"I think we all feel in our hearts that we have to take action," said logistics coordinator Izzy Brown.

"We can't sit here and be silent while the Australian Government makes these massive human rights violations."

This Friday marks six years since the Australian Government's Regional Resettlement Arrangement between Australia and Papua New Guinea, known as the 'PNG Solution', was announced.

An Australian Department of Home Affairs spokesperson said no-one subject to regional processing arrangements will be resettled in Australia.

Ms Brown said she was unsure how the Australian and Papua New Guinean governments would respond to the flotilla.

"There are so many unknowns. It's certainly little boats, big mission … but it's for a good reason," she said.

Two boats will leave Cairns this week, joining another leaving from Darwin to converge on Papua New Guinea.

The Sail 4 Justice 'freedom flotilla' is leaving Cairns and Darwin this week. ( ABC Far North: Marian Faa )

Words of hope hit open water

Cairns' Koharu Arai, 7, and her mother Inge Arnold toured the tiny boat ahead of the voyage.

Koharu gave her letter to the Sail 4 Justice crew at the Cairns wharf yesterday.

"Dear refugees, I'd like to welcome you to Australia. I hope you can come here and be safe," Koharu's message read.

Ms Arnold said her children had struggled to understand Australia's offshore detention regime.

"My kids have really loved being able to find creative and constructive ways to engage with the issue that gives them hope as well," she said.

"This is one way to show them we're not alone in thinking that there's another way to treat people."

Social issues a concern for PNG locals

PNG national Alan Mongerma is concerned about social issues on Manus Island as a result of the refugees' offshore detention. ( ABC Far North: Marian Faa )

Papua New Guinean national Alan Mongerma said he was compelled to support the flotilla because offshore processing policy and detention regime had created social problems on Manus Island.

"You have conflicts between the locals themselves, and then the locals and the refuges, and you have unwanted pregnancies," he said.

"There are so many issues that have occurred because of the centre."

Mr Mongerma said millions of dollars spent on refugee processing had not helped locals.

Last month, the PNG and Australian Governments agreed to extend a $423 million security contract on Manus for a limited time.

The decision followed complaints by security workers of underpayment and poor employment conditions.

"At the end of the day the detention centre is there to serve the interests of the political powers and not our people," Mr Mongerma said.

"We have a shortage of classroom desks, teachers are not getting paid well.

"Then you have the issues of the bridges and roads, shortages of medicine … there's so many issues there."

Home Affairs responded to Mr Mongerma's concerns, saying a significant number of PNG nationals are employed by contracted service providers on Manus.

"The PNG Immigration and Citizenship Authority works closely with the Manus Provincial Government regarding the management of transferees on Manus, including impacts on the Manus community," a spokesperson said.

Ms Brown said the group was planning to meet with Manusian community leaders and church groups on the island.

"The locals have actually been calling for an end to this insanity and I think PNG is really ready to move on this issue," she said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 5 minutes 57 seconds 5 m Manus officials demand action after spike in self-harm ( Natalie Whiting )

Welcome from Indigenous elders

Ms Brown said more than 400 Aboriginal passports would be also presented to refugees as a gesture of welcome from Australia's Indigenous community.

South Coast Yuin Aboriginal man Lyle Davis said a number of Indigenous elders had shown support for the cause.

"I didn't cede my sovereignty, so I don't know what gives the white Australian Government the right to say who can or can't come into this country," he said.

After months of planning, Lazy Jack captain Mic Mandias is nervous and excited to set sail.

"I'm sh**ting myself," he said.

Lazy Jack captain Mic Mandias turned to sailing after he lost his leg in a motorcycle accident in Vietnam. ( ABC Far North: Marian Faa )

"But I think if I wasn't, it would be a very bad thing."

He said he was confident the vessel was up to the job.

"She's built like a tank and keeps taking all the weather that has been thrown at her so far," Mr Mandias said.

"We have satellite phones, we have all the safety equipment. I think we're even carrying three EPIRB life rafts. I think we've got everything on board."

Mr Mandias bought the boat two years ago after losing his leg in a motorcycle accident while travelling around Vietnam.

"I was getting annoyed about the future and decided to buy a boat," he said.

"It's been built out of many different types of timber. The floor is made from coastal banksia, tea tree in the roof, the hull is spotted gum with a jarrah keel."

Mr Mandias said the flotilla was a peaceful way to protest Australia's offshore detention regime.