BT's infrastructure subsidiary Openreach has been criticised by Vodafone over its rollout of its G.fast technology.
Openreach is currently deploying G.fast as part of an effort to achieve faster broadband speeds over the existing copper network.
However, Vodafone believes that the trials of this technology breach rules set by industry watchdog Ofcom, the Financial Times reports.
As a result, it has called on the regulator to intervene and carry out a proper consultation into this issue.
Openreach has responded by accusing Vodafone of trying to "delay the rollout of ultrafast broadband to ten million premises".
"This is an unhealthy move that benefits no one," a spokesman commented.
An Ofcom official added that it is aware of Vodafone's concerns and will "consider them very carefully".
This is the latest display of antipathy towards Openreach from Vodafone, which is already part of the Fix Britain's Internet campaign, along with Sky and TalkTalk.
The campaign is actively pushing for a full structural separation of Openreach and BT, after Ofcom stopped short of calling for this option.
Instead, the regulator has ordered BT to give more independence and investment powers to Openreach, with the broadband subsidiary being run as a distinct and legally separate company with its own board.
The watchdog believes its proposals will provide Openreach with the greatest possible degree of independence without separating the companies entirely, and lead to decisions being taken for the good of its customers and the wider telecoms industry.
Much of the criticism directed at Openreach from rival firms has been based on its reluctance to abandon old copper lines and run fibre optic cables straight to the home.
Clive Selley, Chief Executive of Openreach, recently acknowledged that fibre is superior to copper and insisted he is a "big fan" of the technology.
However, he stated that supplying it to every home across the country would cost tens of billions of pounds and that G.fast technology can deliver ultrafast speeds at a much lower cost.