A set of twins separated at birth in Indonesia when they were put up for adoption and who found each other this year in Sweden have discovered they have another 12 siblings, the two said on Monday.

"We spoke to our biological mother this spring on Skype. She is around 65 years old. We have 11 brothers and sisters in Indonesia and one brother who was put up for adoption," Emelie Falck, 29, told AFP.

"My biological mother said that my 14-month-old son was her 22nd grandchild," added her twin sister Lin Backlund.

The twins found each other earlier this year in Sweden, living in two nearby towns.

The Skype conference with four of the sisters was "moving", Lin said. "Our mother said that she had waited for this day and that she had hoped to see us again."

Falck said the sisters now want to find their brother who was also given up for adoption.

"He is the last piece of the puzzle... His family name at birth was Rajiman but we don't know what his name is today."

According to several reports, the man could live in the Netherlands, having been adopted by a Dutch couple.

It would mean a lot "to share this with him since we now know that there is a large family in Indonesia that would be happy to see us. I hope that we can find him and that we can all be reunited," said Backlund.

"Lin and I have a good relationship because we're twins but also because we're geographically close to one another. If we can find him, I hope that he'd want to become part of our lives," Falck added.

"I don't know a lot about my (biological) father. We've only been told that he works a lot and that he no longer lives in the same place as our biological mother. They weren't married when they put us up for adoption," said Backlund.

In February, the twins told AFP about the story of their own reunion, which prompted the Indonesian press to identify their biological mother.