Lengthy queues at Heathrow have cleared overnight - but further concerns were raised about the reputation of the airport with the Olympics on the horizon.
Immigration Minister Damian Green is to be grilled by MPs about the chronic queues, it was announced, after reports of long queues to get past passport control again this week.
Keith Vaz, chairman of the Home Affairs Select Committee, told BBC Radio 4's Today programme: "There is a real problem and the problem has emerged over the last few months.
"I'm not saying we should abandon checks, but it's a choice for the Government - you either look at the way you deal with people when they arrive at Heathrow or you recruit more staff.
"This is not just about the Olympics, this is about what happens before and after, it's about Heathrow as a world-class airport and it's about our reputation, and we need to make sure we get it sorted."
The Labour MP said that queues of more than half an hour were not acceptable.
"I would have thought by the time you get off a plane and you've walked a long way from the plane to immigration, half an hour would be a problem.
"Anything from zero minutes and 30 minutes would probably be acceptable but people would expect to get through much quicker."
A spokeswoman for BAA, which owns Heathrow, said Friday night's long queues, which saw passengers waiting for up to an hour, had cleared by midnight.
Discussing the situation, she said: "Everything is looking quite good in the immigration halls. Things are moving and we haven't got major queues."