Royal Mail has scotched claims that two million parcels and letters have been lost or delayed in the Christmas post.
The last recommended day for first class Christmas mail was 20 December
It was alleged in a Sunday Times report that customers across the UK faced a Christmas without gifts or cards.
The newspaper said the boom in online shopping and postal workers failing to deliver presents to save time on their rounds was to blame.
A Royal Mail spokesman said the claims "completely distorted the picture". He said that deliveries were "on track".
The last recommended day for posting First Class Christmas mail was 20 December.
After that, the Royal Mail will not guarantee that post will reach its destination by 25 December.
"Royal Mail is on track to deliver by Christmas all of the Christmas mail posted by the recommended last posting date," said David Simpson, head of media relations at Royal Mail.
He added: "Our postmen and women have already delivered the vast bulk of this year's Christmas mail bag."
Mr Simpson estimated that the quantity of post this Christmas would be similar to that of last year, with about two billion items in the post.
He said Royal Mail planned 12 months ahead for the period, employing 20,000 extra workers and putting on more train services, overnight flights and 4,500 extra vehicles.
"We pull out all the stops for Christmas."
The UK's 27 million online shoppers are expected to have spent £15bn online in the shopping frenzy that precedes Christmas Day, up 60% on last year, according to Interactive Media and Retail Group (IMRG), the industry body for the electronic retail community.
Royal Mail has predicted that it will deliver a record 120 million items ordered over the internet this festive season - double the number handled three years ago.
But there have been claims that postal workers are not always checking to see whether customers are in before leaving a "you were out" card, according to the Sunday Times.
The report said this had created chaos in the last weekend before Christmas, with long queues outside mail depots around the country as people waited to collect undelivered parcels.
Mr Simpson admitted there could have been individual breaches of Royal Mail policy where postal staff failed to get a signature for a delivery, but called the practice "unacceptable".
He added that he had not heard of one case of an item of mail being lost or delayed in the run-up to Christmas.