Yale and union negotiators will discuss union growth during bargaining this week, continuing discussions on what is expected to be one of the most contentious issues as the two sides negotiate new contracts for nearly 4,000 Yale workers.

Negotiators from Yale and locals 34 and 35 will address the potentially contentious issue within the context of a bargaining process designed to eliminate the conflicts that have characterized Yale labor relations over the last 30 years.

Union leaders have repeatedly said they want negotiations over union growth to involve discussions of graduate students and hospital workers trying to form unions, and University leaders have said they would not discuss either group during negotiations with locals 34 and 35, which represent Yale’s clerical, technical, dining hall, service and maintenance workers.

Friday’s discussions of union growth focused on Local 35 job security, according to a statement released on Sunday by union leaders. The contracts for Local 35, which expired in January but have been extended on a month-to-month basis as the negotiations continue, include minimum staffing levels and provisions that ensured job security for all Local 35 workers. Although the contracts have expired, these clauses last until 2006.

“Even though these are more difficult issues, we had a productive day of discussions,” Yale spokeswoman Helaine Klasky said.

Union spokeswoman Deborah Chernoff declined to comment beyond the statement released that stated the topics of bargaining.

Local 34 President Laura Smith did not return repeated phone calls, and Local 35 President Bob Proto declined to answer questions Sunday.

Yale’s vice president for finance and administration, Robert Culver, attended Friday’s bargaining session and plans to participate in the negotiations Monday and Tuesday, Klasky said.

Culver’s participation in the negotiations comes after union leaders expressed discontent earlier this month because Yale had not included top administrators as a part of its negotiating team. At the time Klasky said the administration was in close communication with Yale’s lead negotiator, Brian Tunney. Klasky said Sunday that Culver was attending the union growth sessions because they dealt with long-term institutional issues.

After decades of tumultuous relations between Yale and its unions, leaders from Yale and locals 34 and 35 this year agreed to use a new process called interest-based bargaining, which involves working with a hired labor-management consultant, John Stepp.

Interest-based negotiations, which began in February, are scheduled to last until at least late April. Stepp said negotiators will not address specific wage and benefit issues until after the interest-based phase concludes.