The walkout by 30,000 workers has stopped manufacturing at around 40 firms, many of them major exporters, including ABB, Kone, Rautaruukki, Metso and Wartsilä.
The Federation of Professional and Managerial Staff (YTN) will join the strike on November 7 if no accord is reached by then. This could shut down operations at Nokia, Cargotec and Outokumpu among others. It would bring the total number of strikers to around 50,000.
Interviewed on YLE TV on Friday, Labour Minister Lauri Ihalainen -- a former chair of the SAK labour federation -- urged the two sides to resume talks this weekend.