SOMALI pirates have threatened Australian oceanographers in the Indian ocean and forced them to flee the area, stopping them from conducting vital climate and rainfall research.

The CSIRO says the pirates have rendered the northwest corner of the Indian Ocean off-limits, and has been forced to call on the US and Australian navies to help fill that gap.

The Australian scientists have been dropping robotic floats across the ocean for the past 10 years as part of the CSIRO's contribution to the international Argo project.

The instruments measure ocean temperature and salinity levels down to 2000 feet.

The data is used to determine changes in the ocean, the effects of climate change and can also be used to predict weather patterns.

But increasing pirate activity off the Somali coast over the last 12 months has left a gaping hole in the agency's research.

The CSIRO largely relies on commercial ships to deliver the floats and those ships are now charting a course around the troubled waters.

"It's really dangerous up there, we've had research vessels that have been threatened and had to run for it, we've had vessels that have had to hire armed guards," CSIRO scientist Ann Thresher said yesterday.

The US and Australian navy ships are on the way to the region to deploy 20 of the robotic floats into the no-go zone.

But Dr Thresher says that is just a stop-gap measure.

"The navies are happy to help when they can but it's a difficult process," she said.

"When you've got a commercial vessel going from Melbourne to Germany you know its route.

"The navy is more ad hoc, they go where they need to be and they don't necessarily tell you about it beforehand."

Dr Thresher concedes the Agro project has no long-term solution to the pirates and its research will continue to suffer.

"There is no solution as long as the pirates continue to operate as far offshore as they currently are ... it's a quarter of the Indian Ocean and it's really dangerous up there."

Originally published as CSIRO researchers flee Somali pirates