A 100m-long floating barrage that can trap plastic waste is to be installed 23km off the coast of the Netherlands.
The project will be run by Dutch group Ocean Cleanup, which was formed to help clear the sea of rubbish.
The barrier will be deployed in the second quarter of 2016.
The dam has been subject to "extensive computer modelling" and "scale model testing" in controlled environments. The main objective of the North Sea test is to monitor the behaviour of the device in real-life sea conditions, with a focus on its interaction with waves and currents.
Plastic in the ocean
The motions of the barrier and the loads on the system will be monitored by cameras and sensors.
The barrier is designed to capture and concentrate waste, but to allow marine life to pass through.
The test will help Ocean Cleanup engineers to design the Coastal Pilot, a clean-up system that is to be deployed off the coast of Tsushima Island in Japan.
It will also help to ensure the effectiveness and durability of a large-scale system that will be deployed in the Great Pacific Garbage Patch in 2020. This is a "trash vortex" that is estimated to cover as much as 15 million square kilometres of the Pacific Ocean.
Ocean Cleanup workers search through plastic found at sea
Images via Ocean Cleanup