Intel, the world's biggest chip manufacturer, opened the west Jerusalem plant for installation work before its inauguration on Sunday.
Koby Bahar, the spokesman, said talks had taken place with ultra-Orthodox leaders over the new plant, which will prepare dies as part of the next stage of wafer production.
"Intel has been operating in Jerusalem for 24 years and therefore this plant does not represent a change to the status quo," Bahar said.
"This plant will operate in accordance with our business needs and the law, including on Saturdays."
Past protests have sometimes degenerated into street violence and long negotiations as the authorities struggled to meet the demands of ultra-Orthodox Jews and secular Israeli laws.
Intel, which operates four research and development centres in Israel, is one of Israel's largest exporters, with nearly $1.4bn in 2008.
Intel's $3.5bn Fab 28 chip plant opened late last year in Kiryat Gat in southern Israel.
The new Jerusalem plant will employ 150 people.