Figures released by the Home Office suggest the number of employees in the Passport Office fell from 3,700 in 2010 to 3,164 in 2012. However, it did increase slightly to 3,333 permanent staff in December 2013.
Seven out of 10 workers are expected to take part in the strike, the first to solely involve passport workers since 2008.
Public and Commercial Services Union (PCS) general secretary Mark Serwotka accused the Home Office of taking a "sticking plaster approach" to staffing levels at the Passport Office.
“The staffing crisis in the Passport Office has been obvious to everyone and it shouldn’t have taken a committee of MPs to force the chief executive to meet us," he said. “We’re still a long way off getting a commitment from the agency that it will work with us to put the proper resources in place to ensure these backlogs do not reoccur year after year.”
A statement released by the union also claimed pay levels for passport workers are around £3,000 less than employees doing similar work in other parts of the Home Office. Serwotka added that the Home Office appears to have accepted the argument but the union will have to take a business case to the Treasury.
A spokesperson for the Home Office branded the strike "irresponsible" and warned it could affect peoples' holidays if it causes further delays for passport applications.
"We are disappointed the PCS leadership has called this strike given that the Passport Office has been in discussions with the union on their issues of concern," they added.