The report - a response to an Institute of Fundraising consultation about the revision of its direct marketing code of practice - said that incentives should only be included if they were relevant to the cause and people were told how much they cost.
But Mark Phillips, managing director, Bluefrog said in an open letter to the institute that if "involvement devices" worked they should be included. "Once we start running down the route of detailing how an item costs X or Y, where do we stop?" he wrote.
"Packs cost about 50 pence to produce and mail, press ads cost thousands of pounds, TV ads cost tens of thousands. Why just mention the cost of a pen? Why not the cost of the space in the newspaper or the price of a leaflet?"
He also criticised the idea that charities should only mail supporters twice a year. "Without engagement our fundraising will fail," he added.
"It strikes me that this report smacks of shame and embarrassment. Agencies are here to serve charities, not control them, and we best do that by turning our not inconsiderable intelligence to thinking of ways to improve direct mail."
The letter also queried why Bluefrog was not invited to be part of the group of direct marketers that responded to the consultation and suggests that their report was a challenge to earlier recommendations from a wider group.
"I was under the impression that a working party had put together a series of recommendations for the DM code that included charities AND agencies," wrote Phillips. "Did my colleagues at other agencies not like what it recommended? Is this an attempt to scupper the report?"
Lindsay Boswell, chief executive of the institute, commented: "The essence of what Bluefrog is saying is if it works, shouldn't we do it, and don't we have responsibility to raise as much as we can for the cause. That's one side of an incredible important debate. It's an important point to make and we welcome it."
The consultation closes at the end of December.