The two sides were making last-ditch efforts to iron out differences and conclude the deal, which is subject to approval from union members.
A key issue in the talks is SK Hynix's lucrative bonus scheme.
Last year, SK Hynix agreed to share 10% of its annual operating profit with workers in the form of cash, under an agreement which would be in place for 10 years.
This year, however, management proposed paying more than half of bonuses in shares, with sale restrictions for a set period - a plan that met with union opposition.
In 2026, Hynix workers are set to receive an average payout of 779 million won ($547,127) per worker, according to Reuters calculations.
The SK Hynix spokesperson was not available for comment.
