God of nations, wash my sheets...

Fisher & Paykel washing machines have been able to sing for almost 20 years.

Thanks to social media, the secret that a New Zealand brand of washing machine can sing anthems has been uncovered.

Almost 20 years ago, Fisher & Paykel engineers gave their machines the ability to sing the national anthem for in-store demonstrations.

But the gem was forgotten until an Aucklander rediscovered it and made a YouTube video.

"We've got to show you something amazing that your Fisher & Paykel washing machine can do," the woman in the video says before showing viewers how to activate the function themselves.

Within a day of being uploaded, the video attracted more than 81,500 views.

But it's not just the New Zealand anthem that the machines can sing, they can also warble the Australian and United States anthems.

Fisher & Paykel marketing manager Sonya Aitken said their washing machines had been able to sing for almost 20 years. Engineers developed the feature after receiving their marketing and sales team said they needed to create attention on the shop floor.

"So they came up with this really fun way to draw people to the machines and 20 years later, social media is catching up."

Ms Aitken said since the YouTube video had been uploaded, the company had received calls from around the country.

Some people were worried they'd broken their machines.

Activating the singing feature switches the washer into "demonstration mode" which can only be turned off if people take the plug out of the wall socket for at least 20 seconds.

Ms Aitken found interest in the feature entertaining and said she had no idea how the people who made the video found that their washing machine could sing.

Make it sing

• Hold down power button and the one parallel until all the lights turn on.

• NZ anthem: press temperature up button for 2 seconds.

• Australian anthem: press wash level up for 2 seconds until it beeps then press temperature up button for 2 seconds.

• US anthem: press wash level up 2 seconds until it beeps, repeat pressing wash level up for 2 seconds until it beeps then press temperature up button for 2 seconds.