Supermarket giants Woolworths and Coles have pledged to remove products containing tiny plastic particles called microbeads in Australia as global momentum grows to eliminate them.

Microbeads or microplastics can be found in common scrubs, face washes, soaps and toothpastes.

Billions of the tiny particles are being washed into waterways with little knowledge of product users, and causing havoc in Australia's water systems.

Scientists estimate there are about 300,000 microbeads in an average bottle of face scrub, usually labelled as polyethylene in the product ingredients or HDPE (high-density polyethylene), or even PEHD.

Sometimes they're added as an abrasive for deep cleaning, but often serve no purpose other than for decoration.

Environmental activist Jon Dee is leading a campaign to ban the production of microbeads in Australia.

"Most people you talk to have no idea that the personal care products they are using contain plastic microbeads," he said.

"People think they contain exfoliants like apricot kernels and walnut shells and other natural ingredients but the reality is that these products contain microbeads that are so small that they get through the waste water treatment plants and end up in our waterways and harbours."

Environment Minister Greg Hunt told 7.30 the Government was committed to voluntarily phasing out microbeads.

"I have to confess, it's one of those issues which emerged later than it should have," Mr Hunt said.

Microplastics set against grains of sand to show their actual size. ( UNSW, Vivian Sim )

"We want to work with industry to do this. Already Coles and Woolworths have responded and committed to banning microbeads from their shelves by the end of 2017.

"But we want to see a full national phase out."

But environmentalists say that is not good enough, arguing the Government should mirror the US Government's recent commitment to legislate a formal ban of microbead production by 2018.

"We are not leading the world with ending microbeads," Mr Dee said. "But we are starting on the right path."

"We have seven companies who have publicly pledged to phase out microbeads."

Manufacturers such as Unilever, Johnson & Johnson and The Body Shop have been working to find alternative materials to use in their products.

Scientists find microbeads in Sydney fish

Professor Emma Johnston from the University of New South Wales has found 'big' microplastics in fish from Sydney Harbour.

Researchers from UNSW have previously found microplastics in sediment samples from 27 different sites around Sydney Harbour.

Scientists from UNSW dissect a fish from Sydney's harbour to look for dangerous plastic particles known as microbeads.

At one site, the concentration of microplastics was greater than that found outside a former plastics factory in Sweden.

"The problem with microplastics is that once they are in the waterway and in the sediments, we can't get them out," Professor Johnston said.

"There is no way of filtering all the sediments of every harbour in Australia to remove those plastics."

Professor Johnston said microbeads had been found from the Arctic to the deep sea in hundreds of organisms.

"I think it's time that we removed them from all non-essential products," she said.

"The full extent of their toxicity is still unknown."