The arrests come after more than 5,700 complaints about the websites were made to the Advertising Standards Authority and Citizens Advice.
Most were linked to alleged scams over fees charged for tax return, driving licence and passport applications.
Those held last week under the Fraud Act are on police bail, trading standards officials have announced.
An awareness campaign is also being launched by the government warning people to look out for the misleading internet sites, whose URLs often contain fragments of official web addresses, such as "govuk" or "directgov".
Official government services can be found by searching on the gov.uk website.
Richard Lloyd, executive director of consumer organisation Which? said the copycat websites mislead people into paying potentially hundreds of pounds for services that should be free.
The National Trading Standards Board said it was making it "as difficult as possible" for online hoaxers to operate.
Its chairman Lord Harris said: "We have been working with search engines such as Google and Bing to remove adverts from online search results and we continue to gather intelligence across the country to help tackle this issue.
"We urge you to avoid unofficial websites which could leave you out of pocket or at risk of identity theft."
Consumer affairs minister Jo Swinson said: "It's great that it's becoming easier and more common to use the internet to order official documents such as passports or tax discs, but people should be aware of rogue websites that are out there trying to exploit them and take their hard-earned cash and even put them at risk of identity theft.
"The enforcement action which the National Trading Standards eCrime team has taken demonstrates the  government's commitment to tackling these scammers. We will not let them get away with misleading consumers."
Five people have been arrested as part of a crackdown on websites made to look like official government sites.