Average pay rises in industry have fallen back slightly in recent months to 2.4% and wage freezes have started to creep up, according to new research.
A study of settlements in more than 80 companies, employing almost 11,000 workers, showed the figure falling from 2.5%.
The Engineering Employers Federation said its report also found that almost one in five settlements involved a pay freeze.
Chief economist Lee Hopley said: "Whilst overall settlements are continuing to hover around normal levels, signs of pay freezes increasing could be a first sign of companies responding to the growing economic uncertainty we have seen in the last few months.
"Attention will now turn towards the January bargaining round, where negotiations will again take place against a very cloudy outlook for the sector in the year ahead."
John Morris, chief executive of JAM Recruitment, which helped with the research, added: "The current data seems to reflect an uncertainty among manufacturers. Yet with many British companies competing on quality not cost, access to the most skilled and highly educated employees is one of the most important factors to staying fleet of foot."