Experts have developed a COVID-19 vaccine status document for Australians going overseas, after a domestic version was slammed for being so flawed it could be forged within minutes.

Verizon Business Australia said on Friday it worked with the Australian Passport Office in the Department of Foreign Affairs and Trade to develop the International COVID-19 Vaccination Certificate.

More than 1.3 million certificates have been downloaded in the first month as people look forward to travelling.

The international certificate features a QR (Quick Response) code, which is generated from vaccination information in the Australian Immunisation Register and the traveller's passport details.

The digital signature provided by the QR code is a strong defence against fraud.

Each individual QR code is digitally signed to help protect against tampering and can be validated by most immigration authorities as well as at airline check-ins, Verizon said.

The new international certificate can capture your vaccine status, but it's up to the individual traveller to meet the requirements of what "fully vaccinated" means at your destination.

National vaccination certificates can be found through Medicare Online via myGov, the Medicare Express Plus app or your My Health Record.

Tech expert Richard Nelson found a weakness last year in the Express Plus Medicare application's national COVID-19 digital certificate.

But Services Australia insisted the certificate was robust enough.

Along with forgery by anti-vaxxers wanting fake credentials, identity theft remains a concern with cyber criminals here and abroad seeking access to your bank accounts.

Remember, no one legitimate will ask for your sign-in details, or watch you sign in, Scamwatch says.