AFP - British Airways cabin crew will strike for seven days later this month after failing to reach agreement in a long-running dispute over pay and working conditions, union officials said on Friday.

The Unite union said in a statement that staff would spread the stoppages between March 20 and March 30 and warned that further walkouts may occur after mid-April.

"Strikes are planned for March 20, 21 and 22 and further on March 27, 28, 29 and 30," senior Unite official Len McCluskey said in the release.

"There will be no strikes over the Easter period, as we already promised, but further industrial action will be called to take place after April 14 if the dispute has not been resolved," added McCluskey, Unite's assistant general secretary.

Loss-making BA, which is slashing costs to save cash, slammed Unite's announcement which it said would cause massive disruption to travellers in the run-up to the busy Easter holiday period.

"British Airways is extremely disappointed that Unite has announced plans for massive disruption for hundreds of thousands of our customers in the run-up to the Easter holidays," BA said in a separate statement.

"Unite's action has no shred of justification," added the carrier, which is also attempting to merge with Spanish rival Iberia to save money.

Unite is protesting at BA's imposed contractual changes that include fewer cabin crew on flights, a pay freeze and different working conditions for new members of staff.

BA had already won a High Court battle in December to prevent a 12-day walkout by cabin crew over the Christmas and New Year period, after a judge ruled that Unite's staff ballot was invalid.

"British Airways is facing two years of record financial losses," BA continued.

"Unlike other businesses, we have avoided compulsory redundancies and made changes designed to secure a long-term future for our company and our staff."