The money will boost accelerate the Project Gigabit scheme which targets places too expensive for providers to reach in their commercial build and which would otherwise be left behind with poor digital infrastructure.
Contracts worth £288m have already been signed with BT-owned Openreach under the agreement to connect 96,600 home.
Talks are now underway with Openreach to agree further contracts to benefit around 215,800 more premises across the UK.
Secretary of State for Science, Innovation and Technology Peter Kyle said: “Over the past decade, the UK’s broadband rollout has clearly not happened fast enough and has overlooked too many areas, especially in Scotland and Wales.
“Today marks a significant milestone in delivering on our promise to redouble our efforts to achieve full gigabit coverage by 2030.
Clive Selley, CEO of Openreach said: “This is a British infrastructure success story.
“Our network already reaches more than 15 million urban and rural premises and, wherever we build, we bring the widest choice of providers for customers. I’m confident we can reach as many as 30 million homes by the end of the decade if the conditions remain supportive.”