Poison canister washes up on Sydney beach

Another canister of rat poison has washed up on Australia's east coast, this time on a northern Sydney beach.

A resident at Warriewood, on Sydney's northern beaches, found the container some time ago and stored it in his garage.

He rang Triple Zero about 8am (AEDT) on Thursday after Fire and Rescue NSW issued a warning that canisters containing the poison were washing up on NSW and Queensland beaches.

"Aluminium phosphide, which is used as rat poison, can be potentially fatal if it is inhaled or ingested," FRNSW Commissioner Greg Mullins said in a statement.

One of the canisters was discovered on a Batemans Bay beach, on the NSW south coast, earlier this week.

On January 4, a man walking along Salt Beach at Kingscliff, on NSW's far north coast, found one covered in barnacles, lying on the sand.

Based on the barnacle growth, it is believed they have been in the water for some time.

Other canisters have been found on central Queensland beaches over the past 12 months.

NSW Police inquiries have revealed the same canisters have been spotted on beaches in the United States.

The Australian Maritime Safety Authority (AMSA) said it was likely they'd been accidentally lost overboard, rather than dumped.

Aluminium phosphide is often used to fumigate ships.

When the chemical comes into contact with air or moisture it generates a highly toxic and flammable gas, which can be fatal if inhaled.