Since March, drivers caught using their mobile phones face a £200 fine and six points on their licence, an increase from the previous £100 fine and three points.
But the number of dedicated traffic officers has fallen by more almost a third in the past decade, according to The Times, and the decline has accelerated in the past five years.
Figures obtained by the Press Association reveal that more than 200 drivers a day were caught using their mobile phones illegally in the four weeks after the penalties increased -- equivalent to one every seven minutes.
However, some motorists are not deterred by tougher punishments because they do not believe they will be caught, according to the RAC.
Rod Dennis, spokesman for the motoring organisation, said: "Drivers tell us there are not enough police on the roads enforcing driving laws, so inevitably there will be concern that people are getting away with breaking them.
"Illegal mobile phone use at the wheel has been a growing problem in the UK and those that persist in breaking the law need to know there is a real threat of getting caught.
"We welcomed the tougher penalties that came in earlier this year, but to be effective they must be backed up by rigorous enforcement."
Dennis added that stretched police forces are "doing their best under difficult circumstances" but warned that the reduction in roads officers "risks allowing the epidemic of using a hand-held phone at the wheel to continue or even worsen".
Do you see many people using their phone while driving?