A council is to reprint 220,000 new ballot papers after it emerged some were sent to people living in a different part of the North West.
Papers showed Stockport candidates contesting Oldham wards
Ballot papers with the names of candidates for Stockport Council were sent to voters in Oldham by mistake.
Stockport Council said it would arrange urgent delivery to households of its new papers.
The printers who made up the ballot packs have admitted there have been "serious service failures".
The error comes as returning officers in Oldham, Tameside and Warrington decided to deliver ballot packs by hand instead of posting them.
Royal Mail has said it cannot guarantee delivery of all packs by the Tuesday deadline because they were not printed in time.
Stockport Council's chief executive and returning officer, John Schultz, said: "We have identified significant numbers of incorrect ballot packs.
"In view of the scale of the printing problems, we are reprinting and reissuing to every voter in Stockport.
"This has been very disappointing, as all our earlier preparations have been well within the deadlines we were set.
"We are doing everything possible to meet the statutory deadline.
"Our election staff have a very detailed and rigid checking system and there is no possibility of anybody's vote being counted twice."
Electors who have already received ballot packs should return it to the town hall and use the replacement pack instead.
Those who have already filled in their ballot and returned it should fill in the new ballot pack instead.
The council also advised people who are about to go on holiday who only have the first ballot pack to make their vote and return the ballot pack to the Town Hall, unless it is clearly incorrect.