A group of 24 Irish people are in a Western Australian detention centre awaiting deportation after seven of them were caught up in alleged roofing and repair scams.

Five men and two boys, both aged 17, were arrested yesterday over allegations they had been posing as employees of a legitimate roof repair business and attempting to rip off elderly residents in the suburbs of Perth.

Police said on Friday a further 19 Irish nationals, all women and children, had been detained by the department of immigration and border protection.

“All 26 of these overseas nationals have had their visas cancelled and they are remanded pending deportation to Ireland, ” a police spokeswoman said. However, two were subsequently released.

The police searched several caravans at a tourist park in the suburb of Hazelmere on Thursday morning, and seized trucks, building equipment, AU$120,000 (€84,554) in cash and two Rolex watches, worth about $36,000 (AU$25,000). The police then notified immigration officials.

A woman from the tourist park said the Irish families were “lovely to deal with” but changed her mind after hearing about the alleged involvement in the roof scam.

“Thank God they’re gone,” she told Fairfax media.

Alina Cavanagh, spokeswoman for the Western Australia department of commerce, said she had received numerous reports of traders with Irish accents attempting to rip off homeowners.

She said Australians were more susceptible to traders involved in scams than people in Europe. “It seems that Australians are very trusting,” she said.

“The roofs have been a favourite in this instance,” she said. “There have been years where we have seen constant driveway laying scams. They were ‘bitumen bandits’.”

Western Australia’s consumer protection commissioner Anne Driscoll issued a public warning about the scam last week.

She said the traders had used “high pressure sales pitches” to convince consumers to agree to have their roofs repaired at a supposedly low cost.

“The cost of the job is often more than it’s worth and the work is usually sub-standard,” she said.

The men allegedly told homeowners their roofs needed repair and gave them a business card that used the name of a genuine roofing company. However, the firm says the men were not employed by the company.

In an updated statement, Western Australia’s consumer protection agency said it had received 39 reports of travelling traders relating to the alleged scam, 29 of which were made after it issued the public warning.

An elderly man said he had paid AU$17,000 (€11,987) to the men to have his home and driveway painted. They allegedly painted the driveway but did not return to finish the job. Another senior citizen paid $12,000 (€8,500) to have a roof repaired but said the task was not completed.

In some cases the homeowners said the men had damaged their roofs.

In several incidents, the men allegedly went to a bank with the elderly customers and waited while they withdrew the cash to pay them.