BEIJING is arranging to repatriate 659 Chinese nationals detained aboard three ships off the Mexican coast to prevent them landing in the United States, where they could seek political asylum. The decision follows the announcement by Mexican authorities that the illegals would be temporarily admitted to Mexico for speedy repatriation back to China. Chinese Foreign Ministry spokesman Wu Jianmin said yesterday Beijing was talking with Mexico City about taking the Chinese home. After days of bitter dispute between the United States and Mexico, Mexican authorities announced they would take the stranded Chinese, but only to repatriate them. The ships' crews will be jailed on immigrant-smuggling charges, Foreign Undersecretary Andres Rozental said. The agreement will send a tough message back to the smuggling syndicates of China's coastal provinces. The Washington administration is now believed to be preparing to follow through with legislation that would dramatically reverse its previously liberal policy of allowing all arrivals the chance to claim political asylum. It emerged that Mexico had requested China's help in taking back the aliens as soon as possible - without them being screened to determine whether they were eligible for asylum. Mexico's announcement came only one day after angry Foreign Ministry officials said they would refuse to take the migrants. The announcement said that for ''humanitarian'' reasons, and because of growing concern at the conditions on board the three vessels, Mexico had decided to let the migrants ashore. An official at the Mexican embassy in Washington told the South China Morning Post that all migrants were expected to be returned to China, and that Beijing had been asked to start the process as soon as possible. Mexico would bear the cost of the repatriation flights, he said. The crew of the three ships would be questioned, and might be charged. State Department spokesman Joe Snyder said: ''We welcome Mexico's humanitarian action.'' He said that by intercepting the ships off the Mexican coast last week, one important aspect of Mr Clinton's tough new policy had been implemented. ''This communicates to the organisers and victims [of the smuggling boats] that this will not pay.'' The US administration wants to get tougher by passing a law which would allow immigration officers to screen suspected illegals quickly, and if necessary send them home on the next aircraft. Such a move would virtually end the long-standing policy whichallows all arrivals, once they have ''touched base'', to apply for asylum - a process which can take years. Yesterday, Mr Bill Frelik of the Washington-based US Committee for Refugees said: ''If Mexico is going to send them back, both they and the US are in violation of international law'' which states that all migrants should be allowed the right to claim asylum.