Home secretary Theresa May issued an apology for delays in processing passport applications but insisted the government is doing all it can to deal with the situation.
“I am sorry and the government is sorry,” she told MPs in a Labour-led Commons debate on the delays.
There had been unusually high demand for passports, she said.
But shadow home secretary Yvette Cooper described the situation as a “shambles” and accused May of incompetence.
“She has come to this late. She hasn’t had her eye on the ball,” Cooper told Parliament.
“It is really unfair on people who have saved up everything for their holiday and now it’s being wrecked by her incompetence.
“We still don’t know when things will be back to normal, families still don’t know how long they can expect to wait and we still don’t know whether the Home Office has a grip.”
May said the passport office was dealing with the highest demand for passports for 12 years. She said the annual surge in demand in summer had started much earlier than usual.
There are currently 493,289 outstanding passport applications against 146,939 this time last year with a backlog of 346,350, the BBC reported.
May said: “I would like to say to anybody who is unable to travel because of a delay in processing their passport application that I am sorry and the government is sorry for the inconvenience they have suffered and we are doing all we can to put things right.”
The majority of applicants are still receiving their passports within three weeks as usual despite some lengthy delays, May said.
More than 99% of those making “straightforward” applications over the first five months of the year had received their documents within four weeks, she added.
The government has promised to “fast-track” delayed applications free of charge for those in urgent need because of imminent travel plans.
May said: “To qualify, they must have booked to travel in the next seven days, and they will need to provide proof of their travel plans.
“The upgrade will be available until further notice, and I can tell the House that since its introduction, 800 customers have used it to ensure that they receive their passports.”