The organisation has written to Nisa-Today's chairman Dudley Ramsden, renewing calls for the venture to be terminated. It has held unofficial regional meetings across the UK to provide Nisa-Today's retailers and wholesalers with a forum to air their concerns about the proposed merger.
In the letter, leaked to The Grocer, NMA chairman Mark Proudfoot, joint MD of The Grocer Top 50 independent Proudfoots, says: "Our soundings and polls indicate that the proposals will be rejected by far in excess of the necessary 25% of the membership, which means they will fail."
Proudfoot said the NMA was concerned about the amount of time and cash being spent on what it sees as a doomed project.
All retail and wholesale members of Nisa-Today's are shareholders. The Nisa-Today's board expects to clear due diligence for the deal shortly and wants to put the proposal before shareholders in September. It needs the support of at least 75% of them in order to proceed.
A source close to the board said: "How can people be against a deal that hasn't been put to them yet?
"The sort of things being put to people at these meetings are incredibly speculative and unhelpful."
He said the Nisa-Today's board remained fully committed to the merger and that it wanted to hear the views of all members, not just a proportion. He added: "To call for termination of the deal before the full facts have emerged is illogical."
One of the concerns opponents of the deal have is the level of debt it would entail.
However, Nisa-Today's may be able to alleviate this through its ongoing plans to sell warehouses in Scunthorpe.
One insider confirmed the company was in the process of selling a redundant 170,000 sq ft ambient warehouse for about £6m to a property firm. It is understood a sale and leaseback of the active 625,000 sq ft Project Vision warehouse is being considered.Booths denies rumours
Edwin Booth, chairman of Booths, has quashed speculation that the company is cutting supply links with Nisa-Today's.
Reports from within Nisa-Today's suggested Booths aimed to source all its chilled food from elsewhere and suggested this was linked to its position on the planned merger. But Booth, who is vice chairman of the Nisa-Today's board, denied the claims. He said the rumours had originated from a programme to rationalise ranges and increase locally sourced stocks. The company planned to reduce the amount of chilled produce it sourced from Nisa-Today's by up to 25,000 cases per week, 10% of total chilled deliveries. "We're stocking a lot of duplicated lines. We have always sourced some product directly."