Four academics have been plucked to safety from a crocodile-infested wetland in the Northern Territory after their boat overturned.

The four academics, three of whom were from Charles Darwin University (CDU) and one from the University of Western Australia, were working on a project to map weeds when they got into trouble.

Director of the Research School for the Environment and Livelihoods at CDU, Andrew Campbell, said the group were trying to turn their airboat around a patch of weeds when the craft flipped over.

"In airboats all the weight is sitting up above the water and not down in it," Prof Campbell explained.

"That is fantastic for them getting around shallow water and on top of weeds but it does mean that if the thing starts to tip over for some reason ... they are quite unstable," he said.

The group, who were in an area well known for its crocodiles, set off their emergency beacon at 4pm and authorities kicked into action.

A spokesman for NT Police said one one of their planes spotted the group 13km northwest of Cahills Crossing, near Jabiluka Billabong.

He said no crocodiles could be seen from the air by the pilot but the university researchers were keen not to go too close to the water.

"It is a well known habitat for the walking handbags," he said.

He said the police plane could not rescue the group by themselves but stayed in the area until an RAAF rescue helicopter arrived.

None of the group were seriously harmed during the incident and all were rescued within one hour of them setting off their emergency beacon.