Anyone using a VPN to visit illegal sites or dodge a ban on using unauthorised voice over IP (VoIP) service faces a £400,000 fine or prison under a new law brought in by the United Arab Emirates (UAE).

The text of the new legislation says: "Whoever uses a fraudulent computer network protocol address (IP address) by using a false address or a third-party address by any other means for the purpose of committing a crime or preventing its discovery, shall be punished by temporary imprisonment and a fine of no less than Dh500,000 [£100,000] and not exceeding Dh2,000,000 [£400,000], or either of these two penalties."

However, as the Privacy Online News blog explains, the definition of crime in the UAE includes apparently trivial online actions: "crimes include accessing blocked services or websites, which can only be done with a VPN or proxy, use that the UAE considers fraudulent use of an IP address."

Blocked services include all VoIP services except for Skype, and those provided by the UAE's two main telecom companies, Etisalat and Du. Specifically, people are not allowed to use the VoIP services built into Snapchat, Viber, and WhatsApp in the UAE. The bans seem to be in place purely to ensure that the top two telecom companies' profits are not undermined by the free calls available with messaging apps.

Privacy Online News explains who are likely to suffer the most under the new law: "the millions of migrant workers that have come to rely on using VPNs to access free VoIP. The only officially sanctioned VoIP services, the ones offered by Etislat and Du, have already proven to be cost-prohibitive for the average UAE Internet user." Immigrants represent 88 percent of UAE's population according to the blog post.

As well as hitting the poorest sectors of society hardest, the new legislation is likely to make people think twice about using VPNs for fear of inadvertently breaking the law. Consequently, online users will be more vulnerable to attacks by criminals and to surveillance by governments.

Ars has asked the London embassy of the United Arab Emirates for a comment, but has not yet received any reply. This story will be updated when a response is received.