Ignition characteristics are studied using zero-dimensional equations and are compared for both the ITER89P and ITER93HP scalings with the H-mode power threshold in the International Thermonuclear Experimental Reactor-intermediate design (ITER-ID). With the help of the operation path method on the -T plane, the ignition behaviour for both scalings is compared. The comparison study illustrates that the confinement factor of 2.6-2.9 over the ITER89P scaling is necessary for obtaining the equivalent performance to the ITER93HP scaling with 85% degradation due to an ELMy discharge. If the confinement degradation effect of due to the radiative divertor operation is taken into account, the confinement factor should be increased by up to . This result implies that the `advanced' tokamak operation regime may be required even for MA nominal operation from the outset. Modifications of the plasma shape, the central solenoid and divertor would be necessary to increase the confinement time for reducing the ignition risk. The ignition behaviour for both scalings are entirely different, where the ITER93HP scaling is more favourable for the safer ignited operation. Thus, in this sense, ITER89P scaling is highly recommended for designing the ITER.