A different method of checking passengers arriving at Britain's airports could result in shorter waiting times, MPs have said.
The Commons Home Affairs Select Committee says risk-based checks at the UK's borders should be brought back to help ease airport queues.
A pilot scheme, scrapped in the wake of last year's row over the unauthorised relaxation of security checks, should be brought back and could help process large groups of low-risk school children through immigration much more quickly, a report said.
But the committee warned that risk-based checks should not replace time-consuming and thorough security measures on every passenger simply to ease long waiting times.
It also called for the introduction of "smart zones" - where passengers on low-risk routes are screened before they arrive in the UK on the basis of information provided by carriers - to be brought forward from December this year.
If risk-based checks are not brought back, more Border Force staff may be needed, the committee added.
A report from the committee says: "We believe that it is perfectly possible to maintain robust border controls while operating a risk-based model.
"(Theresa May) should start by immediately reintroducing the pilot she suspended in November 2011.
"The pilot was very limited in terms of which checks it authorised officers to drop at their own discretion but would nonetheless have been effective in processing large, low-risk parties such as schoolchildren through immigration much more quickly."
Theresa May is being urged to reintroduce risk-based checking Keith Vaz, the Labour chairman of the committee, said: "The Home Office must immediately reinstate the risk-based pilot for entry checks that was abandoned by the Home Secretary last November."
Under the abandoned pilot scheme, children from the European Economic Area travelling with their parents or in school parties could avoid being checked against the Home Office Warnings Index (Howi), a database of suspected terrorists and those with adverse immigration histories.
Officials were also authorised to use their discretion over whether or not to read the biometric chip, containing a second photograph, in the passports of EEA nationals.
While initial assessments were positive, with a 10% increase in arrests, a 100% increase in firearms detection and a 48% increase in the detection of forged documents on the same period the previous year, it was scrapped following last year's border security row.
The committee said it was also alarmed that maximum waiting times have been "consistently very high for the last 12 months".
The maximum wait fell below two hours in only three of the previous 12 months, varying between one hour 55 minutes last November to two hours 55 minutes last July, figures showed.
"Maximum queue times of two hours or more should be a rare occurrence, corresponding to extraordinary levels of traffic, a security alert or a problem at one or more major ports," they said.
"It is unacceptable for these long queue times to recur on a monthly basis."
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