BlackBerry and security officials have denied the OS has been banned for restricted use in government, following media reports.
Such a rejection would be bad news for the company, which is relying on the BlackBerry 10 OS and Z10 smartphone to revitalise the firm's fortunes.
Despite sales troubles in the consumer market, BlackBerry has remained a significant player in the enterprise and government space because of its normally impressive security controls.
Its previous handsets had been cleared to handle "restricted" data, and the government is one of BlackBerry's biggest UK customers.
According to a report in The Guardian, the software has been rejected by the UK's Communications-Electronics Security Group (CESG) because it fails to meet standards for "essential work", notably around BlackBerry Balance, a tool to separate work and private content.
However, the CESG denied the evaluation had even started yet. "Discussions with BlackBerry are ongoing about the use of the BlackBerry 10 platform in government," the CESG said in a statement. "We have not yet performed an evaluation of the security of that platform, but we expect to be issuing Platform Guidance in the summer. This will cover a number of platforms including Blackberry 10 (and the use of 'Balance')."
"We have a long standing security partnership with BlackBerry and this gives us confidence that the BlackBerry 10 platform is likely to represent a viable solution for UK Government," it added.
The manufacturer has acknowledged that the CESG has yet to approve the Z10, and noted that the process had recently changed
"We have a long-established relationship with CESG and we remain the only mobile solution approved for use at 'Restricted' when configured in accordance with CESG guidelines," the company said in a statement.
"This level of approval only comes following a process which is rigorous and absolutely necessary given the highly confidential nature of the communications being transmitted," BlackBerry added.
"The current restructuring of this approval process, due to the Government Protective Marking Scheme review and the new CESG Commercial Product Assurance scheme has an impact on the timeline for BlackBerry 10 to receive a similar level of approval."
The company also pointed out that it was given security clearance in the US and Germany.