Google will stop responding directly to data requests from Hong Kong authorities.
The step would mean Google will now treat Hong Kong effectively the same as mainland China in such dealings, the newspaper reported.
The development comes after China's imposition of its national security law in Hong Kong, which has drawn criticism from the administration of President Trump and further raised US-China tensions after Washington's decision to end the former British colony's special status under US law.
In a mail sent to RTHK, the tech giant said: "Since the new national security law was enacted in June, we have not produced data in response to new requests from Hong Kong authorities and that remains the case."
It also said "authorities outside the US may seek data needed for criminal investigations through diplomatic procedures".
The Post reported that Google notified Hong Kong police on Thursday that it would direct officials to pursue any requests for data through a Mutual Legal Assistance Treaty with the US, which involves routing them through the US Justice Department, the report added.
In July, Facebook
, Google and Twitter suspended processing government requests for user data in Hong Kong.