THE jump in illegal immigration has alarmed both the Hongkong and Chinese governments, which have agreed to increase co-operation and the exchange of information. The news came as the Director of Immigration, Mr Laurence Leung Min-yin, vowed to crack down on corruption after five of his officers were arrested on suspicion of accepting bribes in an illegal immigration racket. Mr Leung said China and Hongkong were concerned about rising illegal immigration. ''The problem is getting worse. The [daily] average is already 109, compared to 97 for the whole of 1992,'' he said. Nearly 35,000 people were arrested last year for sneaking across the border illegally. The figure is approaching 15,000 for the first five months of this year. Mr Leung said both sides had agreed to exchange information on the routes and origins of illegals. His counterpart in the Ministry of Public Security, Mr Mao Fengping, will visit Hongkong this year. While refusing to comment on case details, Mr Leung said information had been passed to the Independent Commission Against Corruption which led to the arrest of five immigration officers on suspicion of accepting bribes. The ICAC has not laid charges.