In a statement, New Zealand String Quartet Trust chairperson Jeremy Johnson said Helene Pohl and Rolf Gjelsten had acknowledged they did not manage "serious and sensitive issues", especially around conflicts of interest while teaching at the School of Music in Wellington.
"Following Te Herenga Waka-Victoria University of Wellington (VUW) raising serious issues of concern, the New Zealand String Quartet Trust Board initiated an independent employment investigation into the past conduct of Helene Pohl and Rolf Gjelsten.
"Helene and Rolf have offered their resignations, which the board has accepted."
The statement noted that the couple understood their conduct fell short of the values of the New Zealand String Quartet Trust as well as the university's Staff Conduct Policy.
The musicians - who are married and have performed with the group for 30 years - are also long-time members of staff at Victoria University of Wellington's School of Music.
They would be replaced in the quartet's forthcoming season by guest artists.
"Where possible the Quartet intends to fulfil its remaining 2024 engagements and to present its 2025 season with the addition of special guest artists as it commences the recruitment process for new permanent players to join the ensemble."
RNZ has approached Victoria University for comment.