Invisibility cloaks are usually found in the fictional world of Harry Potter, but scientists have shown off their version by making a goldfish and a cat disappear.

In video footage of the device in action, a goldfish suddenly appears as it swims out of a cloak submerged in a tank of water and then the lower half of a cat disappears as it steps inside a cloak placed on a table.

"When swimming inside the cloak, the goldfish becomes invisible and does not block the scene of green plants behind the cloak," the scientists wrote.

The cloak, which was developed by scientists at Nanyan Technological University in Singapore, uses panels of glass to make objects invisible by bending light around them.

The researchers say the cloaks can be adjusted to make objects disappear from any line of sight. They added that the devices could have important "security, entertainment and surveillance applications".

However, the basic device can only make objects vanish from certain angles and the cloaks are partially visible.

Sir John Pendry, an Imperial college scientists who first developed the technology used for the invisibility cloak in 2006, said the work was "a genuine step forward" and that the technology could be used for more serious purposes than hiding pet animals.