Gordon Brown condemned the seven days of planned walkouts as BA and the Unite union met in a last ditch bid to avert the action.
He said: "It's the wrong time, it’s unjustified, it’s deplorable, we should not have a strike.
"It's not in the company's interest, it's not in the workers' interest and it's certainly not in the national interest."
"I hope that this strike will be called off."
He echoed the views of transport secretary Andrew Adonis who launched an attack on the planned action.
He called on Unite, the union representing BA staff, to restart talks and call off the seven-day strike – set to begin on 20 March – because the “stakes were too high”.
Adonis said that he “absolutely deplored the strike” and that it “posed a threat to one of the country’s greatest companies”.
It is the first time a Labour minister has been so outspoken against Unite, which is Labour’s biggest donor. And last night Prime Minister Gordon Brown was facing increasing political pressure to add his weight to Adonis’ stand.
In a response to Adonis, a spokesperson from Unite said: "Lord Adonis appears badly informed. We all want to avoid strike action and Unite is always ready to negotiate. Unite was preparing to put BA’s offer to our members. Had they accepted it, there would be no strikes."
Lengthy negotiations between Unite and BA failed on Friday and the union said crew members would walk out of the job for three days on 20 March and a further four days from 24 March.
The two parties first became embroiled in strike negotiations last year over chief executive Willie Walsh’s plans to save £62.5m by moving staff to part-time, reducing on board staff on long-haul flights from 15 to 14 and freezing the pay of three-quarters of BA crew.
Unite told BA that crew were prepared to take a 2.6 per cent pay cut, but the airline said last week that it "fell significantly short of the £60m savings".
BA said that it was extremely disappointed in staff’s decision to strike and that hundreds of thousands of customers would be disrupted in the run-up to Easter.
A statement from BA said: "Unite's action has no shred of justification. British Airways’ crew are rightly renowned for their professionalism and skills. Our entire package for crew recognises that and is reasonable and fair."
The airline went on to say that it had faced two years of record financial losses, but did not have to make any redundancies.
Conservative chairman Eric Pickles called on Gordon Brown to condemn the strike and suspend its financial relationship with the union until the dispute is settled.