Hello Suresh,
We did find a solution that should work for you. You can define it as:
<ns2:postalCode>2018</ns2:postalCode>
<ns2:provinceName>NSW</ns2:provinceName>
<ns2:countryCode>AU</ns2:countryCode>
That additional province name will better pinpoint the location.
Cheers,
Nadine Wang, Google Ads API Team

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