The importance to Australia's economy of certain multi-million-dollar industries may be hampering efforts to protect threatened marine life and birds, a Senate inquiry has been told.

A federal parliamentary committee is investigating the threat of marine plastic pollution in Australia and its waters, and is holding its first hearing in Sydney.

The inquiry has heard evidence from five ecologists and scientists that microplastics or microbeads can affect the health of humans and marine animals.

These range from inflammation, to breaks in an animal's DNA and ultimately death.

The tiny particles can be found in common scrubs, face washes, soaps and toothpastes.

Billions of the particles are polluting Australia's waterways with little knowledge on the part of the end users of products, and researchers last year highlighted the effect of microbeads in Sydney Harbour's ecosystem.

"It's waste management that's the solution to this," Sydney University Emeritus Professor Tony Underwood, an expert on marine ecology emeritus, told the hearing on Thursday.

People have to say no to plastics, researchers say

Associate Professor Stephen Smith from Southern Cross University said alternative packaging materials had to be identified and people needed to "say no to plastics".

Lord Howe Island naturalist Ian Hutton showed the committee bags filled with plastic rubbish found in the stomachs of animals.

Dr Jennifer Lavers from the University of Tasmania, who worked with Mr Hutton, said their research found that roughly 11 per cent of certain juvenile species they had studied had died as a result of plastics and chemical pollution.

"Flesh-Footed Shearwaters in Australia are kind of like the iconic poster child of the impacts of plastic pollution, yet they do not get a single mention in the Threat Abatement Plan," Dr Lavers said.

She said she has been hitting "roadblocks" in getting species like this listed on the Plan.

Dr Lavers told the inquiry she suspected efforts to protect these types of threatened species will continue to be hampered if they come up against industries worth millions of dollars to Australia's economy.

Dr Lavers said the threat posed to marine life and birds is on par with the risks posed by climate change and rising sea levels.

Federal Environment Minister Greg Hunt announced a "voluntary phase-out" of products containing microbeads by 2018, with the agreement of state and territory ministers.

Woolworths and Coles have also pledged to ban microbeads from their products by the end of next year.