Search scaled back after pregnant woman, partner 'jumped in croc-infested river'

Northern Territory Police have reportedly scaled back their search for a young pregnant woman and her partner originally thought to have jumped into the croc-infested Mary River.

The NT News reports that police are now pursing other lines of inquiry after there have been reported sightings of the missing pair.

Caitlyn Munnich, 19, Raphael Woodhouse, 25, along with three other people allegedly evaded police at a random traffic stop in the Kakadu region.

They managed to evade police for a few hours before fleeing into Bird Billabong in the Mary River early on Saturday morning.

While the three unnamed accomplices are co-operating with police, officers originally held fears the couple jumped into the dangerous river to escape.

However, the NT News reports that early Sunday morning there were reported sightings of the young couple.

"We believe the pair may have jumped into the Mary River and hold grave concerns for their welfare," Territory Duty Superintendent James O'Brien said on Saturday.

"The Mary River system is full of salt water crocodiles and we are hoping that these people have made it to safety."

The river is believed to have one of the highest concentration of crocs in Australia.

The couple excitedly announced on Facebook in July they are expecting a baby.

Ms Munnich is described as being of indigenous appearance, about 160cm tall with long dark hair.

Ms Woodhouse is described as being of indigenous appearance, about 175cm tall and of medium build with short dark hair.

If you have any information about the pair police are urging people to call 131 444 or Crime Stoppers on 1800 333 000.