Around 150 emplyees at the Tata Consumer Products-owned site will walk out, after 88% of union members rejected a deal they said amounted to a pay cut.
A date for the strike action is yet to be revealed by the GMB Union.
A spokesperson for Tata Consumer Products described the decision as “disappointing” in a statement.
They said: “We are in active discussions with both unions and colleagues and keen to further discussions to reach a resolution in line with what’s reasonably affordable to the business and in the best interests of the factory.
“We must remain competitive to support the best long-term future for the factory, and our aspirations to grow Tetley’s presence in the UK and overseas. We are continuing to invest in the site to expand its capabilities and deliver more sustainable packaging, improved quality, and plant-based teabags.”
The spokesperson added that the company was working on contingency plans to allow production to continue with “minimal disruption”.
“Through our global manufacturing network, we will ensure Tetley tea is available for the millions of UK consumers who enjoy a cup of Tetley,” they added.
When balloting was initially announced last week, Laura Maughan, GMB organiser, said some of its members were having to resort to food banks to make ends meet.
“Tetley workers have faced years of real terms pay cuts,” she said. “Now, during a cost of living crisis, they have overwhelmingly refused to take another.
“GMB members are struggling to support their families, unable to escape from domestic abuse in some cases and are having to resort to food banks. All they’re asking for is fair pay for their skilled work.”
“Their quality of life has been eroded over time, and it’s in Tata’s power to change this for the workers, their families and for the future of decent paid jobs in Teesside.”