Immigration Minister Peter Dutton has confirmed an asylum seeker boat en route to Australia has been stopped by the Sri Lankan Navy.

The Navy reported that six adults and three children were onboard the boat when it was stopped on April 19 in the waters west of Negambo.

The passengers – five men, one woman, two boys and one girl – have since been handed over to police for further investigations.

Dutton told 2GB radio the boat had left a Sri Lankan port, but was stopped before it reached international waters.

"The Sri Lankan Navy intercepted that boat, turned it around and took them back to shore," he said.

"It just shows you that the people are still there … We're dealing with these on-water matters all the time."

The report follows the sentencing of a convicted people smuggler in Western Australia.

The 44-year-old Iraqi man appeared before the District Court of Western Australia, where he was sentenced to 10 years in prison.

In a statement, Dutton said the man had been extradited from Germany in 2014 after an investigation identified his role in organising a "people smuggling venture" in 2010.

"There are currently 18 people serving a sentence in Australian prisons for a people smuggling offence," he said.

(ABC)