There's a big problem with the new $5 note.

It’s already caused problems at vending machines, parking stations and pokies, and now the new $5 note is proving problematic for major retailers as well.

According to The Daily Telegraph, the high-tech currency is being rejected by self-serve check outs around Australia.

Supermarket giant Woolworths has reportedly been forced to shell out a whopping $20 million to update 100,000 machines as a result, while Kmarts are still routinely refusing to accept the note.

The new design, which was introduced to circulation on September 1, contains numerous features designed to curb counterfeiting, including the full-length clear strip that slices through the centre.

And as Nick Aronis, president of the National Vending Association, explained to The Daily Telegraph, it’s precisely that which is proving so problematic for machines.

“The note-reader starts to read the note and sees the clear strip. It identifies that as the end of the note and of course it can’t recognise it, so it spits it back out,” he said.

This world-first feature will be rolled out across all denominations as they too are upgraded over the next four years.

Each will also follow the fiver in featuring raised dots to assist visually impaired people easily identify the different notes.