IT workers in Manchester staged a strike on Monday in a dispute over pay and conditions.
The Amicus union claimed more than 250 people were involved in the walkout at high-tech firm Fujitsu's West Gorton plant.
But the company insisted the numbers involved in the the one-day stoppage, which happened after negotiations broke down, was less than 100.
The union believes the latest package of offers from the company would have meant concessions from their members, including giving up employment security agreements.
But the company, which employs 850 staff at the site, said it was "disappointed" the union took the action because it felt it had acted on a number of union demands.
'No pay rise'
The union claims that up to one in three workers at the site are paid less than the company's own minimum pay scales.
Ian Allinson, of Amicus, said the union was "close to agreement" with the company during talks earlier this month but the firm's final offer was "unacceptable".
"Workers at Fujitsu have been left with no alternative but to begin industrial action," he said.
"Some of the workers at West Gorton are facing a second year without a pay rise. Some earn as little as £11,000-a-year."
Union members have withdrawn their goodwill at the site and currently a further half-day strike is due to take place before the end of September.
A Fujitsu spokesman said: "Various meetings have been taking place since the beginning of September to resolve these issues, and discussions are ongoing.
"So we are extremely disappointed that strike action is being taken by the union."