So many dead grey whales have washed up along parts of the US coastline this year that authorities have asked waterfront residents to volunteer their properties as a disposal site for the carcasses.

Key points: The carcasses can be up to 12 metres long and may take months to decompose

The carcasses can be up to 12 metres long and may take months to decompose A resident who has said yes to the request says the smell "isn't that bad"

A resident who has said yes to the request says the smell "isn't that bad" The amount of whales found dead along the US west coast is the highest in about 20 years

At least one Washington state landowner has agreed to the request from the National Oceanic and Atmospheric Administration Fisheries, which said it had run out of places to take the dead whales.

By allowing the carcasses to decompose in front of their homes, landowners could support the natural process of the marine environment, and skeletons left behind could be used for educational purposes, officials said.

The carcasses can be up to 12 metres long and can take months to decay.

Landowner Mario Rivera of Port Hadlock, Washington, told local media the smell was intermittent and "isn't that bad".

"It is really a unique opportunity to have this here on the beach and monitor it and see how fast it goes," his wife Stefanie Worwag said.

The federal agency said about 30 whales had been stranded on Washington's coast this year, the most in two decades.

About 70 whales had been found dead this year along California, Oregon, Washington and Alaska, the most since 2000.

About five were found further north along beaches in Canada's British Columbia province.

It is a small fraction of the total number because most sink or wash up in remote areas and are unrecorded.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 34 seconds 34 s In May another grey whale washed up on a San Francisco beach, making it the ninth in two months

NOAA Fisheries late last month declared the die-off an "unusual mortality event" and provided additional resources to respond to the deaths.

"With the unusual mortality event of these grey whales, we know more whales will be coming in, or there is a high likelihood that more whales will die within Puget Sound and out on the coast," said Betsy Carlson of the Port Townsend Marine Science Centre.

Officials said the grey whale population remained strong at about 27,000.

Lime is being used to help break down the whale carcass on the beach near where Mr Rivera and Ms Worwag live.

"The lime appears to be working," Mr Rivera said.

"It is decomposing nicely. I think."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 48 seconds 48 s Sharks are attracted to whale carcasses in the ocean, but not those buried at beaches

ABC/AP