ROBBERIES and burglaries have jumped, perhaps by as much as 25 per cent, in the New Territories over the past six weeks, police sources say. The increase, described yesterday by a senior police officer as a ''correction'', follows a long period of falling crime. However, wounding with assault appears to be a constant problem with attacks in the past three months jumping 10 per cent from 444 to 487 offences. ''It is usually the first target that comes along,'' one source commented on the nature of crime. ''In the New Territories the same laws apply as in the rest of Hong Kong but the policing experience has a different feel. ''These are not usually planned crimes, but more the quick cash crimes; the instant, opportunistic offences.'' Apart from the recent rises, overall reported crime between February and April fell 4.3 per cent when compared to the same period in 1993. Robberies dropped 5.3 per cent, from 646 to 612. Burglaries were down 21 per cent, from 1,254 to 901 offences. ''It is my perception there are many more illegal immigrants up here than at the same time last year,'' another officer said. ''But I don't think we can read too much into six weeks' figures.'' At Tai Hing yesterday a 15-year-old youth was arrested during an alleged burglary attempt. The New Territories, with towering new developments adjacent to remote closed-shop village settlements, remain vulnerable to sporadic, opportunistic crimes by illegal immigrants. Under geographical police commands it is split into two regions - north and south. Specialist teams patrol the border. The Police Tactical Unit, the force's paramilitary brigade, is based at Fanling. Around Yuen Long, police have long encountered strife from traditional leaders and villages determined to enforce self-rule. In contrast, in Tuen Mun the high number of commuters sees tower blocks virtually deserted during the day - except for juveniles and aged people. Juvenile crime in the New Territories is a matter of concern to police. It is widely conceded more officers could be deployed to the New Territories.