The Covid-19 vaccine pass system may be able to integrate additional passes, like a negative test, in the future, according to an expert.

From this morning, anyone who is fully vaccinated against Covid-19 will be able to request a vaccination pass, dubbed "My Vaccine Pass".

"The pass infrastructure is designed so that other passes could be added to it, this could include a negative test result in the future," Technologist Andrew Chen told Nine to Noon.

He also explained the difference between a vaccine pass and a vaccine certificate.

"The first thing to note about a [vaccine] certificate is that this is what is being used in many juristictions around the world it is a document that contains your personal details and a record of all of your vaccinations... so that people can apply their own rules for whether or not you should be allowed to enter a venue or event."

However, Chen said the Ministry of Health decided that a vaccine certificate would not be needed for domestic use and a vaccine pass would suffice.

"The distinction here is that a pass doesn't actually contain any of your vaccination information it just says that at the time this pass was issued the government considers that this person is fully vaccinated and eligible to enter venues that would otherwise be protected under the Covid-19 framework."

People on social media have also been reporting their struggle to get their pass as it went live this morning.