Lima was accepted as a party member after SPD officials failed to spot the ploy and the dog was sent a postal ballot form to vote on the coalition deal as well as a number of campaign leaflets from rival camps within the party.
German newspaper Bild, who signed the dog up in an attempt to check the party’s identity checks, used an image of the dog wearing a bright red scarf on its front page under the headline: “This dog can vote on the grand coalition.”
The German tabloid reported how it received a party card after it made an application to become a member of the SPD on February 6.
Personal details included her gender and put her occupation as unemployed and her age at 21, in dog years.
Bild wrote in an emailed statement: “It is not about the dog Lima, but rather about how we at Bild proved how prone to falsification the SPD members’ vote is.
“People who wish to manipulate the vote on a ‘grand coalition’ through criminality could do just the same.”
All SPD party members are entitled to vote in the postal ballot which started on Tuesday and ends on March 2 on a coalition pact for Europe’s biggest economy.
If SPD members reject the deal the party will not be able to share power with the conservatives and either a new election or minority government is likely.
The outcome could therefore spell the end of Merkel’s chances of a fourth term in office.
Yesterday it was widely-reported that the dog would get the right to vote, only for the SPD to confirm that would not be the case.
Andrea Nahles, expected to be chosen as SPD leader in April, was forced to respond to the question posed by Bild about whether manipulation of the vote was possible.
Mrs Nahles said: ”A dog can’t vote.” She added that the party would look into legal steps if there had been deception over a party member’s identity.
The prank is the latest in a series of embarrassments for the SPD.
An opinion poll has found support for the party is so low it is now in third place behind the nationalist Alternative for Germany party (AfD).
The findings mean the SPD’s place as one of the two main parties in Germany is under threat for the first time since World War Two.
Polls in Germany suggest the majority of SPD supporters back a deal with Merkel’s CDU.
If a coalition deal is not reached it could spell the end of Merkel’s chances of fourth term in office.