In a survey carried out on behalf of The Grocer, 50 top UK food and drink manufacturers were asked whether they supported entry to the euro, whether they had changed their stance in the past 12 months, and what they thought of the government's handling of the issue.
The survey showed 38% opposed to Britain joining the euro zone, compared with 28% last year.
Although more than half ­ 56% ­ said they still supported adopting the euro, this figure was down on last year's 69%. Among the 38% that had changed their opinion in the past 12 months, 22% had switched their verdict to a no and 12.5% to a yes.
The others had moved from a firm view to being undecided.
The findings revealed a growing unease at the prospect of monetary union, with most respondents expressing reservations whether they were in favour or against the move.
Those against said that joining would harm business by increasing competition with European manufacturers.
One commented: "My greatest concern is that we lose control over the economy and our ability to make decisions about it."
Another said: "From our business's point of view it would lead to increased costs."
Those in favour of entry were concerned about the impact on the domestic economy and the danger of getting the timing of entry wrong.
"For trading purposes it will be better to join. But I am concerned how it will affect the running of the country and that it could lead to spiralling inflation," was a typical comment.
A handful of respondents expressed more decisive views. One supplier in favour argued: "We have to join to survive ­ we can't go it alone."
The overall picture, however, was one of growing uncertainty and Labour's failure to clarify its stance came under fire from all sides. Respondents accused the government of avoiding the issue, being "scared of losing the referendum" and "making no real effort" and described its handling of the debate as "confused", "poor", and full of "the usual spin".
Summing up the majority view, one respondent complained: "There is no clear direction. I am not happy about the way the government has dealt with the issue. There needs to be more leadership. I feel we need to make a decision to go in and make decisions with Europe, rather than sitting on the sidelines."