A Sydney woman has recorded a group of teen boys on a train belting out a soulful tune and it has since garnered great attention.

Commuter Maria Nichols Bucci has told 7NEWS.com.au she rarely catches the train but did so because she had an appointment in the city.

Watch the video above

During her journey, she came across the teenagers who were singing in unison to what has been described as a traditional Tongan song.

"I was in the carriage in front and heard the boys singing in the next carriage," she explained.

"So I decided to walk through to the next carriage where the boys were, not knowing who they are, and I just felt I had to stop and film it.

The teens were singing a traditional Tongan song. Credit: Facebook/Maria Nichols Bucci

"It was so soulful and beautiful coming from these young men," she said.

The woman revealed she believed the high school students needed to be commended for their joyful efforts, particularly during the festive season.

'Had to share'

"Not often you come across a group of boys that aren’t misbehaving and I felt that it was something that needed to be shared," she wrote.

"I hope their parents are proud of them."

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After Ms Bucci shared the footage of the boys on her Facebook page, people from the Tongan community have commented, saying they're "proud" of the boys for singing a church song in public.

The teens, who were travelling to their home town of Cronulla, are yet to be identified.