Beijing has dismissed a report by Japanese defence experts alleging increased naval activity by China as 'irresponsible'. The report has 'ulterior motives', said the Chinese military. China accused Japan of trying to justify its own coastal defence build-up by saying that China posed a security threat. 'The defence paper plays up the 'China threat theory' and has ulterior motives. China expresses its strong opposition to that,' defence ministry spokesman Geng Yansheng said yesterday. Foreign ministry spokesman Ma Zhaoxu said on Wednesday that the Japanese paper made 'carping and irresponsible' comments on China's national defence. 'China's development is offering significant opportunities to all countries in the world, including Japan,' he said. 'I hope Japan can learn from history and seriously reflect on its own national defence policy.' Tokyo's report, which was released on Tuesday, said Japan is concerned with China's growing assertiveness in the South China Sea and the Pacific Ocean. It described China's stance over its conflicting interests with neighbouring countries as overbearing. The report also criticised Beijing for not fully disclosing its military budget. Xinhua said that the 'China-bashing tradition' of Japan had done nothing but jeopardise relations with China and heighten tensions in the region. 'It has also been trying to invoke China's rising power as an excuse to realise military expansion and shake off the yokes of a defence-oriented policy that has been carried out since its defeat in World War II,' the article said. An article in the PLA Daily yesterday said the report was a reflection of 'cold war mindset' among Japanese politicians. 'They are concerned with China's military development and make groundless accusations because they want to find an excuse to build up their military in its southwestern region,' the commentary said. China announced earlier this year that its military spending would increase 12.7 per cent to 601.1 billion yuan (HK$728.1 billion) in 2011. Both Geng and Ma said China's military modernisation programme did not pose a threat. 'China unswervingly adheres to the path of peaceful development, sticks to the policy of building friendship and partnership with neighbouring countries and pursues the defensive nature of its national defence policy,' Geng said. Liu Jiangyong, a professor of international relations at Tsinghua University, said Japan had damaged ties with China. 'Japan is not friendly to China,' he said. 'China's interest will be damaged if Japan moves further to strengthen security ties with the US.'