The Philippines expressed concern Thursday that China may seek control of air space over contested areas of the South China Sea, after Beijing declared an air defence zone above other disputed waters.

Foreign Secretary Albert del Rosario said China's announcement of an Air Defence Identification Zone in the East China Sea on the weekend raised the prospect of it doing the same for the South China Sea.

"There's this threat that China will control the air space (in the South China Sea)," del Rosario said in an interview on ABS-CBN television.

The Philippines, China, Vietnam, Malaysia, Brunei and Taiwan have overlapping claims to parts of the strategically vital and potentially resource-rich South China Sea.

China insists it has sovereign rights to most of the sea, even waters and islands close to its neighbours.

China has been steadily increasing its military and coast guard presence in the sea in recent years to assert its claim, causing diplomatic tensions to rise and stoking concerns in the Philippines about perceived Chinese bullying.

Del Rosario also voiced concern over China's declaration of the air defence zone in the East China Sea, where it is embroiled in a territorial dispute with Japan.

"It transforms an entire air zone into China's domestic air space. And that is an infringement, and compromises the safety of civil aviation," del Rosario said.

"It also compromises the national security of affected states."

The air defence zone requires aircraft to provide their flight plan, declare their nationality and maintain two-way radio communication, or face "emergency defensive measures".

The zone covers Tokyo-controlled islands -- known as Senkaku in Japan and Diaoyu in China -- where ships and aircraft from the two countries already shadow each other.

China's reaction to US B-52 flights 'too slow': media
Beijing (AFP) Nov 28, 2013 - China's response to US B-52 bomber flights in its newly-declared air defence identification zone was "too slow", state-run media said Thursday, calling for Beijing to tackle "psychological battles waged by Washington and Tokyo".

The Pentagon announced Tuesday that two giant long-range Stratofortress planes had flown into China's newly declared Air Defence Identification Zone (ADIZ) in the East China Sea, which includes Japan-administered islands at the heart of a tense dispute between the two neighbours.

The move sent a clear message that Washington would push back against what it considers an aggressive move by Beijing in the region.

Around 11 hours later, China's defence ministry issued a statement saying the Chinese military "monitored the entire process", without expressing regret or anger, and not threatening direct action.

The Global Times, which is close to the ruling Communist Party and often takes a nationalist tone, said the reaction was "too slow".

"We failed in offering a timely and ideal response," it said in the English-language edition.

In a similar article carried in its Chinese-language edition, the newspaper explicitly said that Beijing's statement was "slower than expected" and unprepared, which suggested that Chinese officials were "unskilled" in responding to the US's "psychological battles".

"Chinese authorities must make speedy reactions to various emergencies and challenges," said the English edition.

The state-run China Daily lashed out at Washington's move as fuelling Tokyo's "aggressiveness", warning such tricks risked causing conflict between China and the United States.

"The current mess is a result of Tokyo's brinkmanship, and Washington's 'message' will only add fuel to Tokyo's dangerous belligerence and further eliminate room for diplomatic manoeuvres," it said in an editorial.

"More importantly, it may put China and the US on a collision course. Which will prove much more hazardous than sending military aircraft to play chicken in the air," it added.