Concerns over dangerous game of risk and reward on Australia's northern coastline

On turquoise Top End waters, there is a dangerous game of risk and reward at play.

Illegal boats are sailing across the Arafura Sea from Indonesia to the Northern Territory, some unloading asylum seekers and pillaging Australian waters before sailing home to profit.

The incidents add to growing concerns of an influx of foreign vessels.

Most are illegal fishing boats but people smuggling ventures are making it to the mainland, which is a more recent problem for authorities.

Watch the video in the player above.