The Institute of Civil Engineers (Ice) said elements of the Scottish Government's 20-year investment plan, which aims to upgrade the country's transport, energy, water and other infrastructure, could be threatened by a lack of new recruits.
Its president, Barry Clarke, praised the ambition of the Infrastructure Investment Plan, published in December 2011, but said more needed to be done to persuade young people to train as civil engineers.
The current economic downturn has put the industry's skill base at risk, he said during a speech in Edinburgh. "Minor works, maintenance and major projects all need engineers. There are about 50,000 civil engineers in Britain, around 8000 of whom are in Scotland. But is that enough?"
Mr Clarke pointed to a report last month by the Royal Academy of Engineers that found demand for newly qualified engineers "greatly outstrips supply" and that more than 650,000 would be needed by 2020 to support the UK's economic recovery.
There were 635 civil engineering graduates from Scottish Universities in 2011, an increase of nearly 10% compared to five years earlier, according to figures from the Higher Education Statistics Agency.
A significant proportion of trainees also enter the profession via the college sector.
However, Sara Thiam, Ice's regional director for Scotland, said: "The ageing membership of civil engineers is a huge problem for us. There are probably enough at the moment, particularly given the recession, but we need to make sure there are enough people taking up careers in the industry," she said.
The call was backed by Peter Hughes, chief executive of Scottish Engineering, who said action was needed from primary schools upwards to make the profession more attractive.
However, he said a decline in the number of people taking maths, science and technical studies subject in secondary schools between 2000 and 2006 had been reversed.
A spokesman for the Scottish Government said £1.9 million had been provided for the academic year 2013/14 to support an additional 300 funded university places in science and engineering, and that this would be increased to 1200 additional places by 2015/16.