Scotland's first minister says he has been "assured" by his staff there has been no use of publicly-funded stamps for the SNP's election campaign.
Holyrood officials are investigating the potential use of stamps paid for by MSPs' expenses following a complaint.
Under Holyrood regulations, MSPs are given up to £5,500 annually for stationery and postage costs but are strictly barred from using the cash for party political purposes.
Reports emerged on Sunday that a member of John Swinney's office staff had said the "stamp fairy is very useful when it comes to campaigns" in a WhatsApp group chat with other senior aides.
The Scottish first minister said he had been told by staff there had been no use of the allowance for SNP campaigning.
"I've obviously discussed this with my staff and I've been assured that no parliamentary stamps that have been provided by Parliament have been used to support election purposes," he said on the BBC's Sunday With Laura Kuenssberg.
He described the message referring to the "stamp fairy" as "humorous remarks made in a WhatsApp channel".
"What's important is the reassurance that I've had that parliamentary stamps have not been used for election purposes," he said.
Pushed on whether he was sure there had been no use of public money for the SNP campaign, he said: "I'm confident of that.
"We've obviously been engaging in a fundraising campaign to support the election campaign.
"It's been supported by the many members that we have around the country."
Read more:
Bookies asked for details of election bets of more than £20
Labour candidate's message after office attacked
Cleverly asked about aide who called Rwanda policy 'crap'
'Completely unacceptable'
Speaking to LBC later on Sunday, Mr Swinney agreed it would be "completely unacceptable" for resources to be used in this way.
"The rules are clear that parliamentary stamps that are procured for that purpose should be used for parliamentary activities," he said.
He added it is "important" for those in question to cooperate fully with parliamentary authorities.
Speaking after news of the investigation broke, a spokesman for the Scottish Parliament said: "We take the use of publicly-funded resources very seriously.
"Officials are investigating the matter to establish whether there has been any misuse of parliamentary resources."
Keep up with all the latest news from the UK and around the world by following Sky News
SNP has 'serious questions' to answer
Scottish Tory chairman Craig Hoy said the SNP has "serious questions" to answer over the allegations.
"These leaked messages appear to show staff potentially misusing public resources," he said.
"The SNP must be upfront with parliamentary authorities about this situation."
Disclaimer: The copyright of this article belongs to the original author. Reposting this article is solely for the purpose of information dissemination and does not constitute any investment advice. If there is any infringement, please contact us immediately. We will make corrections or deletions as necessary. Thank you.
