The Labour Party sent campaign leaflets written in Welsh to voters in the Highlands after a Euro election bungle.
Voters received bilingual literature that should have been sent to the Welsh Valleys.
Labour has launched an investigation into the miscommunication, which resulted in Scots being implored in English to “Vote Welsh Labour on Thursday 23rd May”.
The message - “Pleidleisiwch dros Lafur Cymru ar ddydd lan 23 Mai” - was posted alongside a picture of Jeremy Corbyn, who ads: “Theresa May and the Tories are in chaos and Britain is in crisis”.
In Welsh, the message was “Mae Theresa May a’r Toraid mewn anhrefn ac mae Prydain mewn argyfwng.”
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The blunder is the second Scottish/Welsh mix-up by the party in recent months.
A promotional video trumpeting its “vision for Scotland” was illustrated with shots of the Welsh mountains earlier this year.
A Tory spokesman said: “This is yet another embarrassment for Richard Leonard.
“Labour seems to have a habit of confusing Wales with Scotland. It does not exactly inspire confidence.“
Aberdeen North SNP MP Kirsty Blackman said: “We already knew Labour had lost their way politically, but now it seems they’re just lost.
“Mistakes happen, we know that all too well. But last week, Labour were all too quick to criticise us. Let’s see what they’ve got to say about sending out leaflets in Welsh to Scottish households.
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“And this is the second time in a few months Labour HQ have muddled up Scotland and Wales.
“The devolved nations of the UK are treated appallingly by the Tories. But Labour are proving they care just as little.”
A Scottish Labour spokesman said: “A small batch of leaflets were mistakenly sent to the wrong location and we’re looking into how this happened. Most importantly, no personal data was shared.”
