Preseli Pembrokeshire AM Paul Davies has issued a plea that five extra trains a day planned between Fishguard and Carmarthen are made a top priority.
A Welsh Assembly committee looking into the future of rail use in Wales has said that improving train services in west Wales is vital. Mr Davies has now highlighted the recommendation in the Senedd and asked that the government acts on it quickly.
"The five additional daily trains would radically improve the mobility of those who have no car to access work and leisure and of families who have no car to use while the wage-earner uses it for work," he said.
"They would also be hugely beneficial to the elderly and the vulnerable, who might feel that driving along increasingly congested rural roads is becoming more and more difficult.
"Undoubtedly, these additional services would improve people's access to health and education facilities at Carmarthen and Swansea, and the additional trains would improve our economic situation in Pembrokeshire, increasing job opportunities because of more reasonable daily commuting times, and improving journey times generally between north Pembrokeshire and the rest of Wales."
Mr Davies also called for an hourly service between Swansea and Milford Haven to be introduced.