Up to 1,000 HP employees will take part in a four-day strike later this month over pay, conditions and job security.
The Public and Commercial Services Union (PCSU) said yesterday that the HP staff, who work on government contracts in the north east and north west, will walk out on 29 and 30 March and 6 and 7 April.
The industrial action follows three days of strikes that have already taken place as part of an ongoing dispute since January.
The PCSU claims that the previous action affected HP's 'always on' IT that supports mission-critical services used by the UK benefits and frauds office. HP's service was down for a few hours, and the PCSU alleged that this disrupted important IT system updates for the Department for Work and Pensions.
"Staff have worked hard to help the company deliver billions of pounds in revenues, and feel betrayed by HP's refusal to address concerns on jobs and pay, " said Mark Serwotka, PCSU general secretary.
"The escalation of their campaign illustrates the determination of HP staff to achieve guarantees on job security and a fair pay rise. The company needs to start valuing its own workforce and negotiate a settlement that addresses the concerns of the workforce."
The problem for HP is that its former EDS employees are pushing for the UK strike action via the PCSU.
HP has been involved in ongoing disputes since acquiring EDS in 2008 and rebadging the team as HP Enterprise Services.
The PCSU and HP have been trying to resolve the dispute for several months to no avail, even with the involvement of the Advisory, Conciliation and Arbitration Service (Acas).
The union will also be launching a petition and seeking the support of MPs.
IBM and Technical University of Munich team demonstrate how Shor's algorithm, which can't be cracked by conventional computers, can be solved quickly with quantum computing
Hubble Space Telescope finds superflares from young red dwarfs could strip away planetary atmosphere
Younger stars are 100 to 1,000 times more energetic than when they're older
Two of the big four supermarkets will use the system to control sales of restricted products
PUBG news and updates: November's Update #23 to bring new Skorpion pistol and changes to blue zone visibility
Genuinely useful side-arm coming to PUBG in Update #23