An Indonesian couple reunited with their daughter 10 years after a tsunami snatched her from their arms claimed Tuesday to have found their son, who was also swept away in the disaster.

Jamaliah and her husband Septi Rangkuti had an emotional reunion Monday with the teenager they believe is their long-lost son, bringing their whole family together for the first time in 10 years.

Arif Pratama Rangkuti, now 17, was carried off with his younger sister when the devastating 2004 Indian Ocean tsunami slammed into Indonesia's westernmost Aceh province, killing more than 170,000 people there and tens of thousands in other countries.

Arif's sister Raudhatul Jannah was reunited with the parents in June after a relative spotted a girl in an Aceh village who bore a striking resemblance to her.

On Tuesday the couple said their son had now also been returned, thanks to this month's huge media coverage of their "miracle" reunion with their daughter.

"It's true, he's our son. We're now preparing to take him home," Rangkuti told AFP, explaining that the boy had lived for years as a street kid on the island of Sumatra.

Jamaliah, speaking in the town of Payakumbuh in West Sumatra province, wept as she clutched the teenager, who seemed shy and overwhelmed.

"I prayed every night, because inside I believed that my child was still alive," she told reporters.

"My husband has always been restless at home because of this. He would say that our son is still alive."

The family were reunited at the home of a couple who found the boy one night asleep outside the Internet cafe they run in Payakumbuh.

The teenager has lived homeless for years, sleeping in outdoor markets and abandoned shops.

Lana Bestari and Windu Fajri let the boy sleep at their Internet cafe for several months, giving him food and clothes on his regular visits.

- 'God has given us a miracle ' -

Bestari got in touch with the family after she saw a photograph of Arif as a child on television.

Even after ten years, she said she instantly recognised the tsunami victim as the boy who had slept at her cafe.

"I was shocked -- there was a photo of a boy I recognised very well. I recorded his image on my smartphone," she said.

The boy had only told her he had come from Medan in North Sumatra province. If he is indeed the couple's son, it is unclear how he made the journey there from Aceh.

After seeing the news, Bestari and her husband searched for the boy, whom they had named Ucok.

The teenager spoke to Jamaliah and Septi Rangkuti on the phone and the couple immediately travelled to meet him, along with their youngest son and their newly-found daughter, now aged 14.

When the tsunami hit their home in Aceh, Arif and his sister were swept away clinging to a board, according to their parents, who had long abandoned any hope of finding either child alive.

The couple now believe the children were rescued together by fishermen who took them to the Banyak Islands off the coast of Aceh.

The girl was taken in by a family in Aceh, who renamed her Wenni.

A fisherman wanted to adopt both of them, but ended up taking just Jannah as he did not think his family could provide for two more children.

Jannah was reunited with her parents in June after a relative spotted her as she walked home from school.

"God has given us a miracle," Jamaliah said earlier this month after finding her daughter.