Claims that all-postal votes for the June elections are proving a "shambles" have been dismissed as ministers insisted the deadlines would be met.
Will ballot papers arrive in time?
Constitutional Affairs Minister Chris Leslie told MPs technical problems had caused delays in the printing of some postal ballot papers.
But he said: "I am confident that the elections will run smoothly."
Tory spokesman Bernard Jenkin accused Mr Leslie of "phoney confidence" and said some people would lose their vote.
Ahead of Mr Leslie's statement to MPs, Commons Leader Peter Hain said: "I reject entirely the charge that there is chaos in any of the postal vote regions."
The statement was prompted after it emerged more than a million people in northern England may not receive papers for the postal pilots until after the weekend after a printing firm missed a Royal Mail deadline.
Labour's Graham Allen said the delays were "unforgivable" and would not be acceptable in a "fledgling third world democracy".
Although the delay is down to a supplier missing a deadline, opposition MPs are blaming the government for pushing ahead with large-scale postal voting trials to a tight deadline, against expert advice.
Conservative regions spokesman Bernard Jenkin said Deputy Prime Minister John Prescott had been repeatedly warned about the dangers.
Yorkshire and Humberside
The Electoral Commission did not want the pilots to take place in four regions for reasons like this but the government chose to ignore that advice.
Mr Jenkin said people going on a fortnights holiday would be disenfranchised because of the delays.
Britain's "great democracy is beginning to seem more like a banana republic", he added.
Liberal Democrat spokesman David Heath said rules to prevent bias by stopping campaign material from any particular parties arriving at the same time as ballot papers were now at risk.
"This was an avoidable disaster had the minister listened more to the expert advice of the Electoral Commission and his House and not acceded to the bullying of the deputy prime minister," he added.
The Green Party meanwhile is worried that ballot papers are often arriving before official election mailshots - so people vote before they have a chance to read about candidates' platforms.
Mr Leslie accused the opposition spokesmen of "hysteria".
Despite the delays, the printing was on track to meet the 1 June deadline, he said.
He added: "I am confident that the deadlines to hand over [ballot] packs to the Royal Mail will be met."
Mr Leslie said printing was still going on in 49 of the 127 local councils involved in the all-postal voting pilots.
He claimed the vast majority of voters in the four pilot regions were receiving their ballot papers.
Mr Leslie refused to go into the possible legal implications if the ballot papers were not delivered in time.
Opposition MPs suggested further delays could require the recall of Parliament during its break next week.
On Wednesday Tony Blair said he was "confident" people would receive their ballot papers in time.
But he pledged to investigate any delays after Daventry Conservative MP Tim Boswell said voters in the East Midlands "did not have a prayer" of receiving their ballots before the weekend.
Other areas reporting problems with late delivery include Warrington, Chester, Preston and Gateshead, where an expected delivery of half a million ballot papers had not arrived. Contrary to some reports there were no problems expected in Blackburn.
Warrington Council said it was preparing to bring in extra staff to bypass the postal system and deliver papers by hand to individual houses, but there are concerns the papers will not be delivered by the promised deadline of this weekend.
Voters have until 8 June to post their ballot papers, although they can give them by hand to the returning officer until polls close on 10 June.