The wheels of government in China and Japan often turn slowly, but when it comes to fixing perhaps the most dangerous faultline in relations between the two Asian powers, they appear to have ground to a complete halt.

More than a year after Beijing and Tokyo sealed a landmark deal jointly to exploit gas reserves in disputed areas of the East China Sea, officials on the two sides have yet to hold a serious meeting to work out the details of how to implement it.

The lack of action on the June 2008 agreement is troubling. Feuding over gas reserves by Asia's two most energy-hungry economies has for years been seen as a security tinderbox made no less incendiary by its maritime location. Stable Sino-Japanese relations are as important for Asia as Franco-German amity is for Europe – but considerably harder to achieve given a host of unresolved historical issues and the naturally destabilising effect of China's growing economic and military power.

Even more disturbingly, given that growing power, the blame for the gas go-slow lies mainly with Beijing. Over the past 12 months, Japanese government leaders have repeatedly mentioned the need for action on the gas deal during routine exchanges. But their Chinese counterparts have declined to hold any serious sit-downs.

So it remains unclear how the two sides might carry out their joint exploration and eventual development of gas reserves in the area set aside under the deal, or whether Japanese companies will be able to invest in a controversial Chinese gas project.

“We have no idea when they will be ready to move on this,” says a Japanese official familiar with the issue, saying the biggest stumbling block appears to be worries among Beijing policymakers about public opinion.

There is little denying that many Chinese are highly sensitive to any perceived territorial concessions to Japan. Last year's deal was immediately assaulted on the Chinese internet as the work of “traitors”.

Beijing leaders are particularly nervous amid this year's string of politically sensitive anniversaries: of the 1949 founding of the People's Republic, the 1989 crackdown in Tiananmen Square and the 1999 suppression of the Falun Gong sect. “It's quite logical that they don't want to play up the [gas] issue now,” the Japanese official says, charitably.

Yet Tokyo can also be faulted for the delay. Japanese policymakers – often willing to wilt in the face of nationalist pressure – have been largely content to let Beijing put the gas deal on a back-burner rather than risk the ire of homegrown rightwingers who say it is Japan that is being sold out.

Japanese officials saw the 2008 agreement itself as something of a coup, given it marked at least an implicit acceptance by Beijing of the need to engage with Japan's claim that the border between the two countries' exclusive economic zones runs along a “median line” between the two nations. China's claimed EEZ border is based on its continental shelf and runs much closer to Japan's coast.

Japan is reluctant to offer any concessions that might strengthen China's hand in a separate dispute over ownership of a group of uninhabited islands known in Japanese as the Senkaku and in Chinese as the Diaoyu.

Still, officials on both sides can reasonably argue that even without solving anything, the mere sealing of the gas deal drew poison from a long-festering diplomatic wound.

Shi Yinhong, professor of international relations at Renmin University in Beijing, says that while it is clear that neither side is willing to offer further compromises, they are at least determined to avoid escalation. “It's mature management,” Prof Shi says.

Yet there have also been recent reminders of the dangers of inaction. Tokyo has complained about Chinese exploration of areas not covered by the agreement. Protests have been exchanged over the appearance of Chinese survey ships near the Japanese-controlled Senkaku islands and Tokyo's subsequent stationing of a helicopter-equipped coastguard vessel in the area.

So there are good reasons for both sides to match the lofty rhetoric of Wen Jiabao, Chinese premier, who in 2007 pledged to “make the East China Sea a sea of peace, friendship and co-operation”.

Even if the area's vaunted gas reserves do not disappoint, few imagine that the economic benefit they might offer either side could ever be more than a fraction of the potential gains from peaceful and friendly commercial co-operation.

With its population ageing fast and its relative economic edge eroding, Japan would be wise to try to excise any canker from its ties with China earlier rather than later.

For Beijing's part, an uncompromising approach can only further fuel international worries about its rising clout, especially given a sharpening of its tone on territorial claims in the South China Sea in recent months.

Last year's agreement was not easily won: it arrived more than half a year after the expiration of an autumn 2007 deadline set by Mr Wen and Shinzo Abe, then Japanese prime minister. Now the leaders of both sides should set a new deadline for implementation – and this time they should make sure it is kept.