Professor Celia Hoyles, chief adviser to the Department for Education and Skills on maths, told a London conference that students needed clear career advice in order to choose the right A-levels.
"It's not right that children are taking one pathway and then finding they just don't have the skills," she said. "These days children are clear about what they want to do and they need clear advice."
The number of teenagers taking maths has slipped since the 1980s, and university lecturers have said they are being forced to give students catch-up classes because they arrive without the advanced skills they need to study engineering and science.
Professor Robin Wilson of the Open University also spoke at the Institute of Mathematics and its Applications Conference, where he urged mathematicians to do more to make their subject attractive.
Popular television series and books such as Music of the Primes raised the subject's profile, he said.
"The number of people who read the average pure mathematics research paper is less than five," he told delegates.
This year's 300th anniversary of the birth of Swiss mathematician Leonhard Euler (above), was the perfect opportunity to attract publicity to the subject, he said.