The UAE said it would suspend BlackBerry Messenger, email and web browser services from October 11.
The United Arab Emirates is to block sending emails, accessing the internet, and delivering instant messages to other Blackberry handsets.
Saudi Arabia is to prevent the use of the Blackberry to Blackberry instant messaging service.
Both nations are unhappy that they are unable to monitor such communications via the handsets.
This is because the Blackberry handsets automatically send the encrypted data to computer servers outside of the two countries.
The UAE ban is to start in October, while the Saudi move will begin later this month.
Abdulrahman Mazi, a board member of state-controlled Saudi Telecom, has admitted that the decision is intended to put pressure on Blackberry’s Canadian owner, Research in Motion (RIM), to release data from users’ communications “when needed”.
The UAE’s telecoms regulator, TRA, said the lack of compliance with local laws raised “judicial, social and national security concerns”.
RIM has yet to comment on either case.
There are an estimated 500,000 Blackberry users in the UAE, and 400,000 in Saudi Arabia.
TRA said some Blackberry services would be suspended from 11 October “until a solution compatible with local laws is reached”.
“It’s a final decision but we are continuing discussions with them,” said TRA director general Mohammed al-Ghanem.
“Censorship has got nothing to do with this. What we are talking about is suspension due to the lack of compliance with UAE telecommunications regulations.”
It follows an alleged attempt by TRA last year to install spyware on Blackberry handsets.
And in 2007 RIM refused TRA access to the code for RIM’s encrypted networks so it could monitor email and other data.
Media freedom watchdog Reporters Without Borders told the BBC last week that while the UAE was playing a “technological leadership role in the Arab world”, this was backed by “repressive laws” and a “general trend of intensified surveillance”.
BBC Middle East business reporter Ben Thompson said the threat by the UAE was likely an attempt to wring concessions out of RIM.
“Many here see this as little more than a power play from the UAE authorities – an attempt to force RIM to handover the security codes or face losing a lucrative market,” he said.
India has also raised security concerns over Blackberry data services, saying they could be exploited by militants.