LONDON • London's Heathrow Airport has cancelled 172 flights ahead of a planned two-day strike this week, British media reported.

Unite, Britain's largest union, said its 4,000 members have overwhelmingly rejected a revised pay deal ahead of crunch talks between the union and Heathrow Airport bosses, with plans for a walkout tomorrow and on Tuesday likely to go ahead.

The airport, Britain's biggest, pre-emptively cancelled the 172 flights as last-minute talks to avoid the action were being held, according to British newspapers The Telegraph and the Independent.

Heathrow said in a statement that, as part of a contingency plan, it was working with airlines to consolidate and reduce the number of flights operating during the strike period.

The airport said it remains committed to finding a solution with Unite, but charged that "the proposed strike action has been unreasonably designed to impact passengers taking well-deserved holidays".

In a statement, the union warned Heathrow bosses "against opting to pay millions of pounds in compensation to airlines for cancelled flights and causing passenger misery, rather than going the extra mile to give hard-working staff a fair pay rise".

Unite said some 88,000 passengers could be disrupted if 20 per cent of flights are cancelled tomorrow and on Tuesday, amounting to compensation of £2.3 million (S$3.9 million) for airlines affected.

The total bill could double if the union goes ahead with a further 48-hour strike on Aug 23 to 24.