Communicating tensions among incumbents about system innovation in the Dutch dairy sector

•The research shows how innovating incumbents in interaction question and rethink the sector’s sustainability performance.•Several communicative strategies are used when they collectively address and deal with tensions.•Most communication about tensions concern the boundaries between initiative and representatives.•In addition to formal meetings, informal meetings and bilateral communication assist in addressing and dealing with tensions.•Innovation initiatives and assigned staff assist in opening up conversations on tensions hindering sector transformation.