Provider AJ Bell has warned customer complaints would "go through the roof" if mandatory guidance was put in place in its currently proposed form.
Tom Selby, senior analyst at the firm, which provides mainly self-invested personal pensions (Sipp) and platform services, said people would not take well to being stopped from accessing their pension cash at point of retirement.
Mr Selby told FTAdviser the time of delivery of the guidance was too late in life and providers could not be expected to be responsible for referring their clients, as has been proposed.
The idea of guidance by default was raised by the work and pensions select committee in a report out in mid-December.
It was also included in an amendment by the House of Lords to the government’s guidance bill, which is due to be debated in the House of Commons.
The committee, chaired by Frank Field, called on the government to make people either take or expressly opt out of guidance before they can access pension freedoms, akin to the way auto-enrolment works.
The Lords also want to mandate scheme managers and trustees to ask people, at the point at which they seek to access or transfer their pensions, whether they have received information and guidance available to them from the government’s incoming financial guidance body.
If they have not received that guidance, the amendment stated the regulator may require them to provide the individual with access to it before they can proceed with the encashment or transfer request.
The Lords were particularly concerned about the current low take-up of the government's free at retirement guidance service Pension Wise, which was put in place to help people make decisions following the pension reforms.
But Mr Selby said while he backed the idea of encouraging more people to take financial advice and guidance, he did not think the amendment had been structured well.
"The amendment put forward, while undoubtedly well meaning, risks causing huge friction in the market if savers who have decided they want to access their money face an extra barrier," he said.
"A lot of people will have done research on their own and they want to get access [to their cash] as quickly as possible. If you put a barrier in the way people will be annoyed and complaints will go through the roof."
He said the people fighting for the mandatory guidance, including the work and pension select committee and consumer champion and former pensions minister Ros Altmann probably did not appreciate the burden it would present to providers.
"The wording at the moment, where providers would book the appointments on behalf of their clients, that is no small task," he said.
Besides, he said, at point of retirement was not the right moment to be pushing this initiative.
"It needs to fit in with the way people behave [otherwise] a large number of people will opt out.