A U.S. federal regulator has initiated an investigation into a cloud computing deal between Alphabet Inc's Google and Ascension Health which would give Google access to detailed health information of millions of patients, the Wall Street Journal reported.

The Office for Civil Rights in the Department of Health and Human Services will look into the data collection to ensure the partnership is in compliance with the Health Insurance Portability and Accountability Act (HIPAA) which safeguards medical information, the Journal said

On Monday, Google said patient data "cannot and will not be combined with any Google consumer data."

Google did not immediately reply to Reuters' request for comment.