Simon Hart MP has welcomed a £5 billion deal to provide mobile phone coverage for nearly all of Britain within three years.
Not spots mean mobile phone coverage is poor or non-existent in many parts of Carmarthenshire and Pembrokeshire.
Culture Secretary Sajid Javid struck a deal last week (December 18) with four mobile providers to cover 85 per cent of the UK's land mass by 2017.
However, it will be left up to Vodafone, O2, EE and Three to decide where they invest their cash, and Mr Hart said south west Wales needs to be at the forefront of improvements.
He said: "I think that mobile phone coverage has got increasingly worse in the four and a half years that I have been an MP. The difference in reception between London where I work during the week which has 4G and home in Pembrokeshire which has patchy coverage and not even 3G is staggering."
The agreement should radically increase coverage for hundreds of thousands of people in rural areas. At the moment, only 69 per cent of the UK's land mass has coverage.
Mr Hart added: "This deal will make a huge difference to businesses and to everyone in Pembrokeshire and Carmarthenshire and I am delighted that the Government has taken action."
Simon Hart MP
House of Commons
15, St John St
or 0207 219 3000