Party officials blamed a “printing error” for the misleading information.
It was contained in a leaflet sent out by Conservative canvassers in Norwich ahead of the local elections on May 4.
The leaflet said: “You don’t need to take any ID in order to vote, so long as you are registered.”
However, controversial new rules brought in by the government mean that for the first time ever in the UK, anyone voting in person must produce photo ID.
A spokesperson for the Norwich Conservative Federation said: “We would like to express our regret for any confusion resulting from the printing error caused by the unintended use of an incorrect template.
“Our assessment suggests that approximately 250 leaflets were disseminated in Norwich before the issue was identified.
“To rectify the situation, we will produce new copies of the leaflet with accurate information and guarantee that they are delivered to the households that received the incorrect version.”
Lib Dem local government spokesperson Helen Morgan called on Tory chairman Greg Hands to launch an inquiry.
She said: “Not content with disenfranchising people through their divisive and unnecessary voter ID plans, it appears the Conservatives have been wrongly telling people they don’t need photo ID to vote. It shows they are treating voters with total contempt.
“The Conservative Party must launch a proper inquiry to get to the bottom of how these highly misleading leaflets were printed and distributed.”
Meanwhile, it has also emerged that just 4% of the estimated two million people without photo ID applied for a government-approved voter authority certificate before last night’s deadline.
A spokesperson for the Electoral Commission said: “While increases in awareness of the voter ID requirement have been strong, voter authority certificate applications were lower than might have been expected.
“This may reflect the number of people wanting to vote in these elections, take-up of postal or proxy voting, or that some voters have not taken action in time for the deadline.
“We will consider the levels of take-up and the reasons for this as part of our evaluation of the implementation of voter ID.”