We are developing a novel MEMS-magnetoresistive hybrid device aimed at ultra low magnetic field detection. The hybrid device combines magnetoresistive (MR) sensors and AlN based piezoelectric MEMS resonators. The MR sensor can achieve highly sensitive magnetic field detection but suffers from high magnetic and electrical 1/f noise, limiting its applicability for dc and low-frequency field detection. We overcome this problem by using two piezoelectric cantilevers with integrated magnetic flux concentrators (MFC) to mechanically modulate the external magnetic fields into the high frequency region where the 1/f noise in the MR device vanishes. In this paper we report our fabrication approach and preliminary characterization of the hybrid device.