CityFibre has raised concerns about the intended merger between BT and 4G mobile broadband provider EE.
The fibre telecoms provider fears the acquisition of EE could prove bad for competition in the UK broadband sector, reports the Financial Times.
It has told the Competition and Markets Authority of its worries over the future of a deal to supply EE with fibre connections in East Yorkshire.
CityFibre is in the process of building a next-generation network in Hull, where KC - as opposed to BT - is the incumbent telecoms provider.
Under current plans, CityFibre will provide EE and its network-sharing partner Three with high-speed access to its mobile masts.
“Hull was the first city called off on a national framework agreement," CityFibre stated.
"However, post BT/EE the framework has been effectively neutered and the UK is unlikely to benefit from an accelerated rollout of metro fibre."
The firm added that in a post EE/BT world, EE and Three should continue to be able to buy from the provider of best value and choice and not be compelled to take fibre services from BT.
Last week, Greg Mesch, Chief Executive Officer at CityFibre, said it is "vital" the government does all it can to encourage a competitive environment for fibre investment.
He claimed that CityFibre is one of the few companies that is both investing and building next-generation ultra-fast infrastructure, with its rollout of UK Gigabit Cities.
"The CityFibre model is already stimulating ultra-fast rollouts in York with the joint venture with Sky and TalkTalk and in Hull with ultra-fast dark fibre rollouts to mobile masts for Three and EE," Mr Mesch noted.
He claimed that a level playing field - one that enables the next generation of fibre infrastructure builders to invest in ultra-fast broadband networks - will generate greater levels of innovation, services, and growth for towns and cities across the UK.