NICOLA Sturgeon has said that issues people faced with the new vaccine passport app are "deeply regrettable" but insisted the problems were being addressed and the app is now working well.

Scotland's Covid certification scheme came into force at 5am on Friday, October 1 but the enforcement of provisions will not come into effect until October 18 to allow individuals and businesses to get used to the new rules.

The NHS Scotland Covid Status app became available on Thursday, September 30 with many people finding it difficult to use initially as they were unable to find their vaccination records from the information they gave.

The issues were particularly problematic over Thursday evening going into Friday.

READ MORE: Nicola Sturgeon tells Holyrood 'no immediate change' to Covid-19 restrictions

During a Covid update in Holyrood today, the First Minister accepted that this caused "extreme frustration" for people that wanted to download the app quickly and for businesses and event organisers wanting to test their arrangements over the weekend.

Sturgeon told MSPs that the problem was not with the app but with the "NHS systems that it links to".

She said: "Essentially the high level of demand after the launch of the app – combined with an error in one part of the NHS system – meant that information wasn’t being sent quickly enough from the NHS system to the app.

"This also, for a period, caused problems for those requesting paper copies of vaccination certificates, or seeking to download a PDF.

"However, improvements to remedy the problem were made to the NHS system on Friday evening.

"Indeed, I can report that the initial backlog of people waiting for their information to be matched had been cleared by Saturday lunchtime.

"We will of course continue to monitor the performance of the app."

READ MORE: John Swinney says paper vaccine passes remain valid amid app concerns

Responding to a question from Scottish Tory leader Douglas Ross asking how many people had tried to download the app and were unable, and if she would accept that the scheme should have been delayed, the First Minister said: "The app didn't work as we intended it to do last week - there is no point me trying to say anything differently.

"I have tried to set out here, as clearly as possible, the technical reasons for that.

"It is deeply regrettable but action was taken to resolve the issue."

She added that as of midnight on Sunday, October 3, almost 380,000 people had downloaded the NHS Scotland Covid Status app.

READ MORE: Here's how to download Scotland's Covid vaccine passport app

In her statement, Sturgeon added that the Government will continue to engage with businesses and sectors that are subject to requirements for the scheme.

Football clubs said that no fan would be turned away from matches over the weekend if they could not provide evidence of their vaccine status and Sturgeon said that Hearts and Rangers were able to check around 20% of crowds as they tested their arrangements.

Alternatives to the app for people who do not have the information available to use it can request a paper copy of vaccine certification or a PDF version.

These options will continue to be available for anyone who is not willing to use the app.

WATCH: 'Where have you been for 18 months?' Nicola Sturgeon slams Douglas Ross

The first two weeks of the scheme are a grace period in terms of enforcement of the scheme but the Scottish Government is expecting businesses to use this time to "implement and test their approach to using it.

From October 18, the regulations will become enforceable by local authority officers.

Sturgeon said: "Those officers – as has been the case throughout the pandemic – will use what we call the 4 E’s approach. They will Engage, Explain, Encourage and only then - if those options are exhausted - will they Enforce."

The First Minister encouraged individuals to get a copy of their vaccine records "as soon as possible" saying that while the early experience of the app was not good, it now works well and other options are available.