Three Chinese government ships on Monday entered territorial waters around East China Sea islands at the centre of a dispute with Tokyo, Japan's coastguard said.

One of the surveillance ships entered waters around the islands known as the Senkakus in Japan and Diaoyus in China at around 1:32pm (0432 GMT), while another followed about 20 minutes later, the coastguard said.

The third vessel entered the waters around the islands, controlled by Tokyo but claimed by Beijing, at about 2:35 pm (0535 GMT), it said.

The ships were spotted by coastguard aircraft which were patrolling the region, and were later ordered by a Japanese patrol vessel to leave the area, the coastguard said.

In response, the third Chinese vessel reiterated Beijing's claim.

"The ship responded in Chinese by saying in essence that Diaoyu and related islands are an inherent part of Chinese territory," a Japanese coastguard spokesman told AFP.

The three ships were still inside what Japan claims as its territorial waters as of 3:50 pm (0650 GMT), the Japanese coastguard said.

China has repeatedly sailed into waters around the disputed islands since Japan nationalised the chain in September.

Beijing sent its ships into the area as recently as December 21, after the conservative Liberal Democratic Party swept to a landslide election victory in Japan.

Newly elected Prime Minister Shinzo Abe has said he wishes to mend Tokyo's ties with Beijing.

But analysts predict that China is unlikely to change its claim to the islands and will probably continue to send its ships into the surrounding waters to bring the world's attention to the dispute.

Earlier in December, a state-owned Chinese plane breached Japanese airspace over the islands. Tokyo responded by scrambling fighter jets and said it was the first time Beijing had breached its airspace since 1958.