HONG KONG'S prison population has swollen to record levels, with some women's institutions housing more than twice the recommended number of inmates. Newly-emptied Vietnamese detention centres are being used to cope with the overflow, much of which is caused by booming numbers of illegal immigrants, a government spokesman said. The Correctional Services Department (CSD) told the Sunday Morning Post last week its 'ability to maintain order and discipline in prison' was being stretched. Officials are concerned discipline will break down unless the problem is resolved. A senior police officer warned that the daily arrest and jailing of up to 100 illegal immigrants was creating a time bomb. 'The prisons are absolutely packed,' he said. 'If [the penal population] gets too big, it gets uncontrollable.' The CSD has taken over the Vietnamese detention centre at Upper Chi Ma Wan, but the facility is already at more than double its capacity. As other detention centres are cleared by repatriation of boat people, they are expected to be used to house the growing number of convicts until new facilities are built. A CSD spokesman said the situation was 'very serious'. The penal population this month stood at 13,032, with an occupancy rate of 128 per cent, or 28 per cent above the gazetted limit. The figure is for the department's 21 institutions, excluding half-way houses and Vietnamese centres. A Security Branch spokesman said prison overcrowding was placing great stress on staff. 'We have now identified ways to achieve some immediate relief as well as longer-term and more complete solutions,' the spokesman said. 'We will be converting suitable decanted Vietnamese migrant camps into penal institutions, which will provide an extra 450 places by early to mid-1996. 'We will also redevelop the Stanley Prison area to produce 700 extra spaces by 1998.' The measures would reduce overcrowding by 10 per cent. A spokesman for Governor Chris Patten said Mr Patten was being kept fully informed of the 'serious problem'. Assistant Commissioner, Operations, Tsung Pui-kwan said over-crowding was creating extra work, because staffing levels were tied to 'certified accommodation' rather than actual population. 'This stretches the ability to maintain order and discipline in prison, as well as efficiency and services to prisoners,' Mr Tsung said. Facilities for prisoners, such as bathing, dining and recreation rooms, were also greatly stretched, affecting the smooth running of prisons. The most densely populated prison is the women's unit at Upper Chi Ma Wan, which has certified accommodation of 156 but now holds 356, or 228 per cent capacity. Tai Lam Centre for Women also has an occupancy rate of more than double, with 590 women packed into an institution designed for 261. 'Previously all dormitories (at Tai Lam) had 15 beds,' said a CSD spokesman. 'We've turned them into double deckers so we can double the capacity.' Shek Pik Prison, Victoria Prison and Lai Chi Kok Reception Centre are each at least 50 per cent over capacity. Illegal immigrants account for 26 per cent of Hong Kong's penal population, of which 11,428 are men and 1,604 are women. A general rise in the penal population was compounded last year when a policy change meant undocumented mainlanders and foreign prostitutes were jailed instead of deported. Legislator Martin Barrow, who raised the immigrant issue in Legco last week, said the policy should be changed to ensure prostitutes were deported rather than detained. 'These people are costing the taxpayers of Hong Kong an absolute fortune,' Mr Barrow said. Acting Secretary for Security Jim Morris said it cost $22 million a year to keep the territory's 3,300 illegal immigrant prisoners behind bars. There are an estimated 24,000 illegals in Hong Kong at any one time, while the number of prostitutes charged in the territory last year was 1,834, with more than half coming from Thailand. In January, Governor Chris Patten vowed to take action to curb overcrowding which he said had 'reached new heights'.