TAIPEI'S swift return of the hijacked China Southern Airlines plane to the mainland yesterday is likely to ensure that the ''unofficial'' talks between both sides will go on unaffected. And hijacking and mutual crime prevention will be likely to figure in meetings scheduled later this week between representatives of Taiwan's Straits Exchange Foundation (SEF) and Association for Relations Across the Taiwan Straits (ARATS). Taipei officials, however, said Taiwan authorities would prosecute the hijackers in local courts rather than return the two to the mainland, as was demanded by China's Civil Aviation Administration of China (CAAC). Beijing would be irritated by efforts by Taipei to score anti-communist propaganda points about the two hijackers' ''bid for freedom''. In Taipei yesterday, officials said Taiwan's top negotiator with China, Mr Cheyne Chiu, will go ahead with talks in Beijing this week despite the hijacking. Mr Chiu, SEF secretary-general, will visit Beijing today and stay until Sunday as scheduled, SEF spokesman Mr Lee Ching-ping said. Mr Chiu will prepare for an unprecedented meeting in Singapore later this month between SEF chairman Mr Koo Chen-fu and Mr Wang Daohan, head of China's ARATS. The Singapore talks, the first between the heads of the two semi-official bodies handling ties between Taiwan and China, will focus on ways to protect Taiwanese investment in China and on co-operation to fight crime. Mr Wang said yesterday he was willing to exchange views with Mr Koo on signing a formal non-aggression pact between China and Taiwan, according to the Taiwan media. ''The [hijacking] incident and preparations for the Koo-Wang meeting will be dealt with separately,'' SEF's Mr Lee said. Taipei sources said whether the hijacking would affect the talks hinged on the way the two hijackers were dealt with. The culprits were identified as Huang Shugang, 29, and Liu Baocai, 23, both small businessmen from Tangshan, near Beijing. Yesterday, Taiwan premier Mr Lien Chan, and the Taiwan Government spokesman Mr Jason Hu, said the hijacking would be dealt with in accordance with international law. Mr Hu, however, yesterday made much of the fact that the two hijackers had fled to freedom ''due to their hate of communist dictatorship''. ''Preliminary interrogation by airport police showed Liu Baocai and Huang Shugang were determined to risk their lives seeking freedom,'' Mr Hu told reporters. Taipei and Beijing have signed a rough extradition treaty called the Kinmen Agreement, which governs categories of criminals other than hijackers. In May 1988, when Zhang Qingguo and Long Guiyun hijacked a Boeing 737 from Fujian to Taiwan, they were granted political asylum and sentenced to prison terms of 31/2 years, which were suspended. Meanwhile, Mr Wang Zhaoguo, Beijing's Director of the Taiwan Affairs Office, was quoted by two Taiwanese newspapers as saying he would welcome a visit to China by Taiwan President Mr Lee Teng-hui. Mr Wang did not extend a formal invitation to Mr Lee but said China would welcome a visit in his capacity as chairman of the ruling Kuomintang.