Simon Hart MP is calling for urgent action to be taken on dangerous junctions at Red Roses and Llandowror.
He has written to the Welsh Transport minister six times since the new Red Roses by-pass was built – but no action has yet been taken.
"Homeowners from Red Roses, Llandowror and Pendine who have to use these junctions all the time are telling me how dangerous they find them," he said.
Despite repeated requests, the only changes made have been a few extra signs at the westbound approach to Red Roses junction.
"I am frustrated because the Welsh Assembly Government is refusing to release data on these roads – in April this year they told us they were waiting for the 2017 data in order to complete the three-year-safety audit," added Mr Hart. "We are now 11 months into 2018 – how much longer do we have to wait for last year's figures?
It is known that two crashes happened at the Llandowror junction requiring police in 2015 and 2016 and there was a fatal accident close to the Red Roses junction last week.
Mr Hart added: "I have asked for improved lighting at the Llandowror junction and been refused because "there are no indications that this junction has safety problems in the hours of darkness" according to Welsh Transport Minister Ken Skates.
"I have written to him once again asking for the figures and am working closely with the relevant community councils to try to make this road safer."