Miliband plans to reverse the April 2015 inflation-linked rise in small business rates if Labour comes to power the following month; rates would then be frozen at their 2014 level until April 2017.
The rate cut, which is expected to save 1.5m small businesses £450 on average over the two years, would be paid for by scrapping the planned 1% cut in corporation tax, from 21% down to 20%, that is due to come in in April 2015.
Miliband hopes to position Labour as the "party of small business" with the move; however, BPIF chief executive Kathy Woodward said that political parties should be supporting "all businesses - large and small".
"Large businesses are feeders for small businesses and the health of one directly affects the health of the other. What businesses need is consistency to allow them to plan for the future and policy changes - saying we're going to rob Peter to pay Paul - don't help," she added.
"There is a perception that large businesses have all this cash sloshing around, but we know from the print industry that it's often the large businesses that are operating on the lowest margins.
"The government and the opposition should be seeing business strategy as holistic rather than piecemeal; I think what everyone would like to see is an integrated business strategy rather than fragmented pieces of policy that are targeted at winning votes."
Michael Moradian, owner of Print Express, was also sceptical of the proposal.
He said: "They're saying they want to increase help for small businesses and get larger businesses to pay for it; on the face of it, who wouldn't vote for that?
"But 15 years ago who wouldn't have voted for the government to build however many new hospitals? Except nobody realised they were going to be funded by PFIs that were going to screw the healthcare budget for the next 25-30 years.
"It's a nice sentiment and it's hard not to say 'yes, that would be very nice to have', but the devil will be in the detail and I think it's all sleight of hand based on Labour's past record."
Labour estimates that scrapping the corporation tax cut would generate £340m in 2015/16 and £785m in 2016/17 and would affect 80,000 large firms; the small business rate cut would cost £250m in 2015/16 and £540m in 2016/17.
The rate cut, for all commercial properties with an annual rental value of less than £50,000, would apply automatically in England, while money would be given to the devolved governments in Wales, Scotland and Northern Ireland to fund the same cut.