Kosher food wholesaler Hatov Distribution said its margins had been squeezed by a weaker pound against the shekel and dollar and the soaring costs of food production.
However, Manchester manager Yitzi Stefansky echoed the sentiment that a drop in consumer spending was another major factor.
"Shops are taking much less stock because it's been a tough year in sales, which have been nothing like last year or two years ago. People seem to be buying less and going for cheaper products," he observed.
On Sunday at Haber's kosher supermarket in Prestwich, Hatov was promoting its large range of kosher wines through a tasting session highlighting products not available in mainstream supermarkets.
One customer appreciating the difference was Stephanie Grant from Whitefield, who said the small selection of wines in Tesco was one reason for gravitating to the kosher shops.
"I did go to Tesco first, mainly because they had the most products out earliest. But they haven't got ev-erything. I went for the bargains - I got a whole six packs of matzah for free. But I haven't bought their own brands. I'd rather buy Israeli products and support Israel."
Ellis Haft and his wife Annette had travelled to Haber's from Merseyside to stock up on specialist items, although Mr Haft reported good ranges of Pesach products at Liverpool kosher delicatessen Roseman's and nearby Allerton Tesco.
"I'm a coeliac, so I need to buy special products that are gluten-free," he said. "We've also been to both Tescos in Manchester which have Pesach sections, but there doesn't seem to be more than in the kosher shops where we've done most of our shopping.
"We've looked to the supermarkets for the special offers, especially on meat, and their two-for-one offers. I do think the supermarkets offer a service to people who live away from Jewish centres."
Warren Henderson from Prestwich said his shopping patterns had changed little from last year despite starting a family. Low price grape juice had drawn him to Tesco in an effort "to keep down expense" but "there wasn't much difference between most prices and range" compared to independent kosher stores.
Tesco reports that its Pesach sales nationally this year have been "the most successful yet." Kosher foods buying manager Gershon Odze said customers had responded positively to "more promotions than ever before".
His claim appears to be supported by customer reports of tuna selling out in both the Prestwich and Cheetham Hill branches.
"Where products have sold ahead of forecast, we have done everything possible to secure additional stock," Mr Odze explained.
"This year we provided a wider range of products in the provinces as well as in busier Jewish areas because customers have asked us to.
"It's not about challenging anyone else, it's about providing for our customers," he maintained.
