THE police force's annual budget is to rise by more than $120 million, allowing hundreds more officers to go on the beat. The money is on top of expenditure on new facilities and capital investment. The money will come from savings identified by a series of manpower studies conducted by the police in the past 18 months. More than 2,000 recommendations were made in the reports. The dissolution of the Special Branch will save nearly $50 million in the 1994-95 financial year and $70 million the following year. The implementation of information technology will save a further $20 million. The amalgamation of the Field Patrol Detachment and the Frontier District will save $9 million and redeployment of drugs police another $7 million. Some $41 million will come from redeployment of cell guards, station guards and fuel pump attendants by installing modern equipment such as alarm bells, video cameras, automatic gates and fuel pumping machines. ''Hong Kong policemen are the second highest paid in Asia after Japan. We do not give them six months' training to stand guard at gates or to pump fuel,'' a government source said. ''We are willing to invest in modern technology to release manpower from these areas. Money can be redeployed to put hundreds more men on the street.'' Automatic gate bars for police station entrances will cost $75 million, but will free 90 station guards. Special alarms and television monitoring systems will cost $7 million, but will release as many as 200 cell guards from duties. As information technology is gradually implemented, 569 men will be redeployed. The police has 27,000 disciplined staff and 6,000 civilians, but less than 8,000 of them are on the street.