The deal by an American conglomerate to buy the facilities from Hong Kong company CK Hutchison will be reviewed, Chinese antitrust regulator stated on its website.
China’s State Administration for Market Regulationunderscored on Friday that it would scrutinize it "in accordance with the law to protect fair competition in the market and safeguard the public interest”.
Chinese state media has already labelled the potential purchase of the ports of Balboa and Cristobal a threat to national security.
Amid the review, the signing, initially planned for April 2, has been postponed.
The deal is part of a $22.8 billion one whereby CK Hutchison had agreed to sell its 80% stake in subsidiaries managing 43 ports across 23 countries to the consortium led by BlackRock and Global Infrastructure Partners (GIP).
“These world-class ports facilitate global growth... Through our deep connectivity to organizations like Hutchison … and governments around the world, we are increasingly the first call for partners seeking patient, long-term capital. We are thrilled our clients can participate in this investment," said BlackRock CEO Larry Fink in a March statement.