Britain is to move 80 extra staff into border control roles in a bid to ease lengthy queues at Heathrow Airport just weeks before the London Olympics, immigration minister Damian Green said Tuesday.

"As of today, we are instituting some changes," Green said on a visit to the airport to the west of London, where some passengers have been forced in recent days to wait at least 90 minutes to have their passports checked.

"During the course of May we're employing 80 more people," the minister added.

But the Home Office, Britain's interior ministry, clarified that the 80 staff were existing employees of the Border Force government agency who were being moved to frontline jobs from back office roles and other locations.

A majority of the 80 workers will go to Heathrow, the Home Office said.

The delays at the airport, the world's busiest in terms of international passenger traffic and the main gateway for the Olympics which open on July 27, are proving a major embarrassment for the British government.

Frustrated passengers resorted to slow hand-clapping and jeering in queues last week.

Green admitted in parliament on Monday that some passengers from outside the European Union were forced to wait in Heathrow's flagship Terminal 5 on Friday for up to an hour and a half.

But the head of British Airways' parent company accused the government of misleading the public over queueing times, saying some passengers had been forced to wait at Heathrow for up to two and a half hours.

"The government is misleading people," International Airlines Group chief executive Willie Walsh said.

"We have accurate, detailed information that shows that people queued for up to two hours and 31 minutes on Friday night," he told BBC radio.

Green stood by the estimate of waiting times provided by the Border Force, saying: "The figures are as accurate as can be."

The minister, who blamed the delays on the heavy rain that lashed Britain over the weekend which caused flights to bunch together, said the government would not increase the speed of passport checks at the expense of security.

"Security is the number one priority," he said as he visited Heathrow's Terminal 3 during a quiet period. "But after that we have to make sure that the personal experience is as smooth as possible."

Speaking earlier on BBC radio, the minister said he could see "why people are annoyed" but said the government was working to improve the situation, including by building a central control room for the Border Force at Heathrow.

The minister added that he believed Heathrow's owner BAA was in talks with airlines for carriers to fund an increase in Border Force staff.

London mayor Boris Johnson has led complaints about the queues, saying Monday that they gave "a terrible impression of the UK".

The BBC reported that extra staff were brought in from Manchester in northwest England on Tuesday to ease the Heathrow queues, but the journey meant they could only work for four hours each.

AFP