Salvadorean security officials and United States officials here say restoration of US aid to Salvador's internal security forces would heighten the professionalism of those groups and help to improve the human rights situation in El Salvador.
These officials are encouraged that the Broomfield amendment - a bill that would repeal a 10-year-old prohibition on such aid - has cleared the US House of Representatives and is now before the Senate.
''We have long been of the opinion that increased professionalism and training for the state security forces will help the human rights situation here ,'' says US Embassy spokesman Don Hamilton.
The three security forces that would receive new assistance - the National Police, the Treasury Police, and the National Guard - are regarded by some human rights groups and others here to be among the major violators of human rights here. Many Salvadoreans who have been detained by these forces complain of torture and beatings by security officials.
However, US Embassy officials contend that new US assistance will help to bring these forces under control. The security forces are ''beyond our influence , and partly because of this they have the worst record for human rights violations,'' wrote Col. John Waghelstein, the former top US military adviser to El Salvador, in an article in a magazine published by the Heritage Foundation last November.
US Embassy officials and the directors of the three internal security forces here have been calling for reinstatement of the assistance for several months.
The type of aid advocated by these officials and under consideration in the Senate was cut off in 1974 when critics in Congress charged that US-aided security forces in El Salvador, Honduras, Guatemala, Brazil, Uruguay, Chile, and Bolivia repeatedly tortured and assassinated citizens.
''Abuses are committed,'' Col. Nicolas Carranza, the former chief of the Treasury Police, told the Monitor shortly before his transfer from that post last week, ''and there may be some cases of torture, but this is because our men lack training and equipment.''
Colonel Carranza, who in a May 8 Monitor article was cited by a Salvadorean military source as actively involved in death squad activity, said that the conception of the death squads has been ''distorted by the international press and enemies of El Salvador like (former US Ambassador to El Salvador) Robert White.''
''The first time the death squads appeared,'' the Colonel said, dressed in combat fatigues and oufitted with a 45-automatic pistol and huge knife strapped to his hip, ''they appeared in Brazil. Those in the death squads were police officials who shot criminals, mostly thieves. There was no law then and no way to put them in jail. Every time the police arrested someone, they were set free, so crimes went unpaid.
''We, too, found that the justice system did not punish the terrorists here who attacked the population and so we had to take measures on our own.''
Carranza said that the security forces need interrogation rooms with two-way mirrors, tape players to record confessions, and special interrogation equipment such as bright lights. He also said he hoped the US could provide ballistics and explosives-testing equipment.
''If the US began helping the state security forces,'' says Col. Reynaldo Lopez Nuila, director of the National Police and another officer linked to death squad activity in the May 8 Monitor article by the same military source and by a prominent Salvadorean civilian, ''then you would see an increased professionalism and respect for the law by our officers.''
The Broomfield amendment, named for its sponsor, Rep. William S. Broomfield (R) of Michigan, would allocate $20 million in assistance to Central American and Caribbean police forces and require President Reagan to notify Congress 15 days before providing funds to any of the region's police or state security forces.
The House of Representatives passed the measure on May 10. The amendment was inserted in a foreign aid bill authorizing about $200 million in military aid to El Salvador during 1984 and 1985. The amendment was deleted from the bill before it reached the House floor by the Western Hemisphere Affairs Subcommittee. But it was reinstated by Representative Broomfield on the floor. The amendment was not discussed in floor debate.
The program the Reagan administration hopes to see reinstated under the amendment was known as the Office of Public Safety Program (OPS), a program sponsored by the US Agency for International Development (AID). It was designed to ''develop the managerial and operational skills and effectiveness of its civil police forces.''
Between 1957 and the program's termination in 1974, OPS spent $2.1 million to train 448 Salvadorean police, and provide arms, communications equipment, transport vehicles, and riot control gear.
Until 1963 the program was primarily concerned with upgrading the National Police. From 1963 on, the program's focus shifted to the National Guard. Between 1963 and 1965 - when US involvement in the program was at its height - five US advisers were stationed here to oversee training and program management.
When Congress ended the program, saying that OPS was making repressive regimes even more repressive, AID analysts concluded that the ''National Police . . . has advanced from a nondescript barracks-bound group of poorly trained men to a well-disciplined, well-trained and respected uniform corps. It has good riot control capacity, good investigative capacity, good records, and fair communications and mobility. It handles routine law enforcement well.''
Public safety advisers organized the Police School and trained and equipped riot control units in the National Police and National Guard. OPS created a bomb-handling squad within the National Police which was also ''responsible for investigating terrorist activities,'' set up a central police records bureau, and installed a teletype system linking El Salvador, Nicaragua, Honduras, Guatemala, Costa Rica, and Panama.