Eleven allegedly illegal immigrants were arrested when four immigration raids were carried out on Thursday.
Staff working in four different takeaways and restaurants around Shetland were arrested during the eight hour period.
All 11 detainees face possible removal from the country, while their employers face the possibility of steep financial penalties.
Home Office officials confirmed that immigration enforcement officers visited Raba Indian Restaurant, and Mr T’s, both Lerwick, at 1pm; Taj Tandoori, Brae, at 5.30pm and Hai Yang takeaway, Scalloway, at 9.15pm.
Officers were acting on intelligence that all four businesses were employing immigration offenders. Staff at each location were questioned about their right to live and work in the UK.
A Bangladeshi man, 23 and a Nepalese man, 31, were arrested at Raba. The younger man was said to have overstayed his student visa while the older was found to be an immigration offender.
At Mr T’s three men were arrested. Two Nepalese nationals, aged 26 and 37, and a 37-year-old Pakistani man.
Both of the 37-year-old men were said to have entered the country illegally, while the younger man was found to be an immigration offender, according to the Home Office.
At Hai Yang officers arrested five Chinese nationals – four men, aged between 37 and 47, and a 42-year-old woman – all of whom were said to have entered the country illegally.
A 32-year-old Bangladeshi man arrested at the Taj Tandoori was found to have overstayed a visit visa, Home Office officials said.
The five men arrested from the two Lerwick restaurants were detained, pending removal from the UK.
Those found at Taj Tandoori and Hai Yang who have been ordered to report to a police station regularly while steps are taken to remove them.
All four businesses were served notices warning that financial penalties of up to £20,000 per illegal worker found will be imposed unless they can demonstrate that appropriate right to work document checks were carried out.
This could mean a fine of £100,000 for Hai Yang, £60,000 for Mr T’s, £40,000 for the Raba and £20,000 Taj Tandoori.
Stephen Roarty, from the Home Office’s immigration enforcement team said: “This is a clear warning to those in Scotland abusing our immigration laws that, wherever you are in the country, our dedicated and well-resourced teams will find you.
“The use of illegal labour is not victimless. It defrauds the taxpayer, undercuts genuine employers and denies legitimate job hunters work.”
He added: “We are happy to work with employers who want to play by the rules but those who flout them will face heavy financial penalties.”
The operation was carried out in partnership with Police Scotland. More in this week’s Shetland Times.