Size and wavelength dependent photoionisation studies have been carried out on xenon clusters (Xe-n) using nanosecond long gigawatt intensity laser pulses. The ionic species (Xe+, Xe2+, ... Xe10+) were characterized by time-of flight mass spectrometry. It is observed that higher the irradiation wavelength, higher is the maximum observed charge state of xenon ion. Clusters of < Xe-17 > on irradiation with 532 nm pulses yielded only singly charged ions (Xe+, ... Xe-4(+)) whereas < Xe-50 > produced multiply charged Xe ions (Xen+, n = 1-10). With increase in cluster size, kinetic energy of multiply charged xenon ions was found to increase, while the threshold laser intensity for inducing multiple ionisation within the cluster decreases from 9 x 10(9) W/cm(2) for < Xe-50 > to 3 x 10(9) W/cm(2) for < Xe-11400 >. (C) 2012 Elsevier B.V. All rights reserved.