He said: "Building a sub-standard version which only contains some information means it is likely to become a white elephant, with running costs out of all proportion to its usefulness, and we will have failed generations of pension savers in the process."
At the Conservative Party conference, Ms McVey said the government will "be giving people the opportunity to access their pension information through an industry led pension dashboard, building on the government’s check your state pension online service".
DWP declined to comment further.
Kate Smith, head of pensions at Aegon, said the government was looking to minimise taxpayer costs with the project.
However, "plumbing the state pension into the dashboard will be an additional government cost, and one that it should be thinking about".
She said: "The government would also have a role in supporting the setup and ongoing governance of the pension dashboard project, which at the very least would cover the costs of personnel attending meetings.
"It is important the pension dashboard project learns any lessons from the Open Banking initiative. The feasibility study hopefully will be able to address this and many other of the long list of unanswered issues still to be resolved."
Sir Steve Webb, director of policy at Royal London and former pensions minister, agreed with this view.
He said: "As part of the feasibility study it is to be hoped that the DWP have made some realistic assessments of the cost to the public purse of playing their part in the dashboard project.
"At the very least, the government will need to supply state pension data to the dashboard and it is to be hoped that conversations with HMRC about this are at an advanced stage.
"Hopefully the forthcoming feasibility study will answer these questions and will help the project to gather momentum."
For Adrian Boulding, director of retirement strategy at Dunstan Thomas, the stumbling block for the government was not cost, but trust.
He said: "The state pension forecast is already available online to those who have a government digital identity, so it will cost very little to plug that system into the back of the pensions dashboard.
"The stumbling block will be if the government trusts that an industry led dashboard with an industry digital identity is secure enough to allow it to connect to a system currently protected by a government digital identity."
Kay Ingram, director of public policy at national firm LEBC, suggested the oversight of protocols and security of data should be tasked to The Pensions Regulator and to the Financial Conduct Authority jointly.
Ms Ingram also argued that migrating the state pension data wouldn’t involve much extra cost, since "the right technology can make this a seamless process".