The present invention provides a rotary jet cleaning apparatus suitable for use in cleaning pipes and/or boreholes. The apparatus comprises a positive displacement motor (22) and a rotary jetting tool (23) drivingly connected (24) to an output drive part (25) of said motor. The motor has a drive fluid supply conduit (30), and the rotary jetting tool (23) has at least one generally radially outwardly directed nozzle means (43) provided with a jetting fluid supply conduit (29). The jetting fluid supply conduit (29) and drive fluid supply conduit (30) are connected in parallel to a common fluid supply inlet means (40) to said apparatus so that jetting fluid may be supplied to said jetting tool nozzle means substantially without reduction in pressure due to running of the motor for rotation of said jetting tool.
