Firefighters in England and Wales will walk out for six
hours on New Year's Eve
Fire Brigades Union members in England and Wales are to strike on Christmas Eve, New Year's Eve and 3 January in an ongoing row over pensions.
Ministers plan to raise firefighters' retirement age from 55 to 60 and increase their pension contributions.
The government has said that pensions remain "generous".
FBU members also plan an overtime ban - which will be joined by members in Scotland who have a separate dispute about overtime.
The union action follows Saturday's strike by FBU members - the sixth in recent weeks.
Union members in England and Wales will walk out for five hours from 19:00 GMT on 24 December, six hours from 18:30 on 31 December and two hours from 06:30 on 3 January.
'Unworkable and unfair'
FBU members in Scotland will also join those in England and Wales from 19:00 on 27 December to 19:00 on 29 December in refusing to work voluntary overtime.
Negotiations have been continuing in Scotland, making enough progress to avert strikes, but the union said no settlement had been reached.
Most firefighters, who are paid around £1,650 a month, pay at least £320 a month into their pension pots.
From April 2014, contributions will rise for the third consecutive year to more than £340 a month, with many facing another rise of 2.2% in 2015, said the FBU.
Its general secretary Matt Wrack said the strikes would remind the government just how reliant it was on firefighters' professionalism.
He added: "However, there should be no need for industrial action, and it's absurd that firefighters' concerns over pensions have not been addressed already.
"The government must stop claiming they are negotiating when they have refused to talk for two months and insist on forcing through proposals that are unaffordable, unworkable and unfair.
"By simply conceding common sense and allowing firefighters a fair deal, the government could end this industrial action today."
'Damage their reputation'
Fire Minister Brandon Lewis has said that discussions have been "constructive" but that firefighters have gone on strike while the consultation process was still running.
In a statement on Saturday Mr Lewis said that firefighters still enjoyed "one of the most generous public pension schemes".
A firefighter on £29,000 who retires at 60 will receive a pension of £19,000 a year, rising eventually to £26,000 with the state pension, he said.
"An equivalent private pension pot would be worth over half a million pounds and require firefighters to contribute twice as much."
He added: "Only around a third of firefighters voted for industrial action in the FBU's most recent ballot and further strikes serve only to damage the reputation of firefighters with the public they serve."