Hundreds of Border Force officers at London Heathrow, one of the world's biggest airports, will go on strike again for four days from Saturday over working conditions, their union confirmed.

The long-running dispute concerns the introduction of new rosters the union insists are "inflexible", with the upcoming industrial action the latest by the officers over the issue.

Hundreds staged a similar strike in April.

Around 650 members of the Public and Commercial Services (PCS) union working in terminals 2, 3, 4 and 5 will walk out, and then refuse to work overtime for 18 days from September 4.

The PCS noted Friday a recent survey of those set to walk out found four in five of them suffer from stress at work and feel pressured to work longer hours.

"This survey shows how badly our members' wellbeing is being affected by the new roster system," PCS general secretary Fran Heathcote said in a statement.

"These inflexible rosters are preventing parents dropping off and picking up their children from school."

She argued managers could "easily resolve the issue by allowing greater flexibility and by agreeing fixed shifts that give our members the chance to plan their caring responsibilities".

A spokesperson for the interior ministry, which is responsible for the Border Force, said officials were "committed to continuing our conversations with the union so we can find an agreement that works for both the public and staff".

"We will have robust plans in place to minimise disruption where possible, but we urge passengers to check the latest advice from operators before they travel."

The government drafted in military personnel to check passports at six airports including Heathrow just before Christmas in December 2022 when around 1,000 Border Force staff went on strike.