Patrols in the South China Sea by Chinese Air Force jets have become a "regular" practice to improve their combat readiness, an air force spokesperson said on Thursday.

People's Liberation Army (PLA) Air Force spokesperson Shen Jinke was quoted by China News Service as saying that they sent H-6K bombers and other aircraft, including fighters, scouts and tankers to patrol islands and reefs in July.

The air force aims to simulate a combat environment over the sea, improve combat readiness against security threats and protect national sovereignty and security, Shen said.

He added regular air patrols will be conducted over the South China Sea.

In July, the Permanent Court of Arbitration in The Hague ruled against China's claims to territory within the so-called nine-dash line. China refused to participate in the arbitration and considers the tribunal's decision "null and void" with no legally binding force.

Shen said the air force will also "regularize" offshore drills beyond the First Island Chain. Since March 2015, PLA aircraft have flown beyond the chain five times to train in the western Pacific Ocean.

The H-6K bombers also patrolled China's Air Defense Identification Zone over the East China Sea. The air force will maintain air patrols over the zone, without targeting any country, said Shen.