Lateral flow home test kits are unavailable on the UK Government website, despite Scots being urged to get tested for Covid-19.
The Government website on Monday said "there are no more home tests available".
It advised people to "try again later" or to book a test site appointment instead.
One person said on Twitter: "Tried to order a lateral flow test kit and the NHS site says they have no more! What's going on!"
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However, there appeared to be no problems with the availability of PCR home test kits.
Meanwhile, people trying to book a Covid-19 booster jab in England have been advised by the NHS to try later or tomorrow as people faced a queue on the website.
In a tweet, the NHS said: "The Covid vaccine booking service is currently facing extremely high demand so is operating a queuing system.
"For users aged 18-29, please be aware that booking opens on Wednesday 15 Dec. For all others experiencing waits, we would advise trying again later today or tomorrow."
The PA news agency has approached UK Health Security Agency (UKHSA) for comment.
The issues come after Humza Yousaf warned that additional covid measures will be put in place in the wake of the threat posed by the Omicron variant.
Scotland's Health Secretary says that restrictions are "inevitable" but declined to give details, saying the Scottish Government is "working through that".
He also confirmed that First Minister Nicola Sturgeon will give a full update to the Scottish Parliament tomorrow.
