University of Hawaii President M.R.C. Greenwood said contract negotiations with the faculty union are at an impasse and warned that the university may impose a salary cut Jan. 1.

Faculty members and the university have been trying to agree on a new labor contract for the past 15 months.

It’s unclear what options are available to the faculty if the university imposes the pay cut.

Greenwood summarized contract talks in an open letter on Monday, saying she is disappointed by a “deadlock in negotiations.”

In October, the University of Hawaii Professional Assembly, which represents 3,200 UH faculty members, rejected UH’s “last and best final offer” of a 5 percent pay cut, a payroll lag, and a reduction in the state’s contribution to health insurance premiums.

The UH system faces a budget cut of $155 million over the next two fiscal years.