This paper describes the design of a tri-axial microelectromechanical force sensor (FS) that can be mounted on the tip of the guidewire. Piezoresistive silicon nanowires (SiNW) are embedded into a cross cantilever design with a manoeuvrable stylus to allow the detection of force in all directions. The electrical resistance changes in the four SiNWs are used to decode an arbitrary force applied onto the FS. The sensitivity of the device can be improved by two orders of magnitude compared to bulk Si thanks to the giant piezoresistive effects offered by the SiNW. Robustness of the FS is improved due to the novel design by incorporating a mechanical stopper at the tip of the stylus. Finite element analysis (FEM) analysis was used in designing the FS.