BT and EE should be forced to give up a proportion of their radio spectrum when the two service providers combine, Vodafone has claimed.
Jeroen Hoencamp, Chief Executive of the mobile broadband provider, wants industry regulators to intervene once BT's £12 billion takeover of EE is complete.
Speaking to the Financial Times, he warned that BT is in danger of building a telecoms monopoly in the UK, meaning action is needed to safeguard competition.
Both BT and EE hold valuable spectrum needed for the delivery of mobile services, including space in the 800MHz and 2.6GHz bands used to deliver 4G connectivity.
Mr Hoencamp said that, post-acquisition, BT will control 45 per cent of UK spectrum holdings - a figure he believes is too great.
"BT and EE are creating a dominant player in consumer and enterprise," the Vodafone CEO claimed. "There needs to be fair competition."
Mr Hoencamp also wants to see a reduction in wholesale costs for broadband providers using BT's network infrastructure.
Vodafone aims to use the network it acquired from Cable & Wireless two years ago to launch home broadband services.
However, the operator will also need to use BT's wholesale network to reach homes and businesses in parts of the UK it does not cover.