(ii) the spreadover, inclusive of intervals for rest, shall not exceed twelve hours in any one day: Provided that the State Government may, in respect of any or all of the categories of workers referred to in clause (d) of sub- section (2), make rules prescribing the circumstances in which, and the conditions subject to which, the restrictions imposed by clause (i) and clause (ii) shall not apply in order to enable a shift worker to work the whole or part of a subsequent shift in the absence of a worker who has failed to report for duty;