She told the Carrot & Onion Conference in Peterborough (20-21 November) that since taking up the position in June "my number one problem I am having is that people aren't coming to me. In one or two cases I have had to ask suppliers whether they are having problems."
She added: "Lots of small dinners with suppliers have so far been the most productive way to gain people's confidence." But she warned: "A review in two years' time can close me down. It's a big global issue and the rest of the world is looking to us for guidance. I don't want to fail because people are afraid to talk to me."
The biggest issues reported to her to date have been deductions from invoices, which may stem from old promotion campaigns.
"I am telling the retailers: 'That's not paying for goods on time - you can't go back six years, but 12 months is okay.' It is also taking up to six months to put right. I'm having to say: 'Don't sit on the money. Give it back.'"
But in all cases so far, issues that Tacon has raised with the supermarkets have been solved at compliance officer level.
"I would rather that than have to impose fines," she added. "But they recognise that they have to do quite a lot to make sure that they aren't fined."
Sarah Dawson, Horticulture & Potatoes Board chairman, NFU
"Our objectives have much in common with Christine Tacon's and the role of her team is essential, but they are only as good as the information they get. The NFU is pulling together evidence and will be approaching our members for more.
"It dismays me to hear about the abuses that are still rife in the industry. Practices such as 'sales support charges' and 'verbal margin agreements' are stripping millions of pounds out of the supply chain every year.
"Also, suppliers shouldn't have to pay more than the retail price for a customer complaint, though everyone knows the figure is more like £20-£50 - and the proliferation of promotions means unnecessary value is being taken out of the chain when demand is high and supply low."