Magneto-transport measurements are performed on the two-dimensional electron system (2DES) in an AlGaAs/GaAs heterostructure. By increasing the magnetic field perpendicular to the 2DES, magnetoresistivity oscillations due to Landau quantisation can be identified just near the direct insulator-quantum Hall (I-QH) transition. However, different mobilities are obtained from the oscillations and transition point. Our study shows that the direct I-QH transition does not always correspond to the onset of strong localisation. * ctliang@phys.ntu.edu.tw and ochiai@faculty.chiba-u.jp PACS numbers: 72.15.Rn, 71.70.Di, The insulator to quantum Hall (I-QH) transition in a two-dimensional electron system (2DES) at low perpendicular magnetic fields B has attracted much attention [1, 2,3,4,5,6,7,8,9,10,11]. Theoretically, the direct I-QH transition from the insulator to an integer QH state of ν = 1 is forbidden in an infinite, non-interacting 2DES with arbitrary amount of disorder, where ν is the Landau level filling factor [1, 2,3]. In such a system, the only allowed state at B = 0 is the insulating one, and the 2DES undergoes the I-QH transition to enter the ν = 1 QH state [12,13]. Realistically, however, only systems of finite sizes are available, and the effects of the electron-electron (e-e) interaction are significant in some 2DESs [4,5,14,15,16,17,18]. As a result, the 2DESs may experience the direct I-QH transition from the low-field insulator to QH states of higher filling factors [2,3,4,8,16,17,18]. Such a transition can be related to the zero-field metal-insulator transition, to which e-e interaction cannot be ignored [4]. Given that most 2DESs show metallic behavior at B=0, the investigation of the direct I-QH transition at low B should be conducted in low-mobility 2DESs [1,12].