The postal workers' union has threatened to continue strike action into the Christmas period unless they can reach a "fair" settlement with Post Office management.
Dave Ward, CWU deputy general secretary, said:
If the Post Office thinks this dispute will simply fade away they are sadly mistaken. The company's plans are to downgrade the network, reduce services to local communities and hit jobs in the network.
Next week's strike and the continuing sales ban activity will continue into the Christmas period unless management see sense and negotiate a fair deal for Crown office staff.
– Dave Ward
The union said next week's strike will affect up to 4,000 staff in 372 offices.
Communication Workers Union spokesperson Andy Furey said Post Office workers did not want to strike, but were determined to "secure a fair settlement." He said he was optimistic about agreement being reached.
The network and sales director at the Post Office has said he is "disappointed" after the Communication Workers Union said its members will launch a fresh wave of strikes from today. Kevin Gilliland added:
This action can only cause disruption to customers, cost our people money and place further pressure on the Crown network which is currently losing £37 million a year.
We must continue with our plans to turn around the Crown network to ensure we keep these branches on high streets and in city centres across the UK.
Workers at Crown post offices will today launch a fresh wave of strikes in an escalating row over jobs, pay and closures.
The Communication Workers Union said its members will walk out in the latest industrial action linked to plans to franchise or close more than 70 Crown sites - the larger branches usually found on high streets.
A UK-wide stoppage will be held today, staff in Scotland will strike on Monday, and union members in England, Wales and Northern Ireland will stop work on Tuesday.
Staff in hundreds of Crown Post Offices will stage a fresh strike today in a long-running row over closures, pay and jobs.
Members of the Communication Workers Union will walk out for half a day from 12.30pm, the eighth round of industrial action since Easter.
The union is campaigning against plans to franchise or close 75 of the Crown offices - the larger branches usually sited in high streets - saying it will hit jobs, and adding that staff have not had a pay rise for more than two years.
CWU deputy general secretary Dave Ward said: "Post Office plans to close offices, cut jobs and reduce services cannot go on unchallenged. It's time that Government stood up for these highly-valued local services which their constituents are signing petitions for in their tens of thousands.
With the news that Post Office staff shared £15.4 million in bonuses, their plans to close offices, cut jobs and refuse to agree a pay rise for Crown office staff is unbelievable.
They're lavishing bonuses at the top while slashing jobs, services and pay for frontline staff. It's blatant fat-cat behaviour from management out of touch with their workforce.
Post Office staff, customers and communities are continuing to stand up for the local Crown post office services they value so highly. The support continues to be enormous. Bosses cannot keep their heads in the sand forever.
– Dave Ward, deputy general secretary of the Communication Workers Union