Continuing the Reagan administration's campaign to do away with federal regulation it believes to be unnecessary, the National Highway Traffic Safety Administration is planning to eliminate two more proposed rules put forward during the Carter administration.

On Monday, the NHTSA is expected to announce its decision to drop a four-year investigation into the safety of automobile batteries. The NHTSA had been considering requiring manufacturers to redesign their batteries -- or at the least put a warning label on them -- to prevent explosions. Battery explosions have caused up to 10,000 consumer injuries a year.

Also on Monday, the traffic-safety agency plans to announce it is ending a proceeding that could have required automakers to install a device on car dashboards to alert drivers when pressure in their tires drops significantly below the recommended level.

These actions, following earlier NHTSA actions rescinding or delaying other key auto-safety and fuel-economy rules, come just weeks before the head of the NHTSA, Raymond A. Peck, is expected to announce his decision concerning auto airbags and other passive car restraints.

Peck is reviewing the controversial rule requiring automatic restraints to be installed in all passenger cars by 1984. Repeal of the regulation is strongly backed by auto manufacturers but vigorously opposed by consumer groups.

Consumer groups also opposed eliminating the battery and tire-warning rules.

In ending the investigation into battery hazards, the NHTSA concluded that significant changes making batteries safer have recently been made in their design.

Among other things, the NHTSA noted that automakers now use maintenance-free batteries with vents that contain flame-arresting devices that inhibit gasses inside the battery from being ignited by fire outside the battery.

However, the Center for Auto Safety, a public-interest group, has charged that these new batteries are responsible for explosions and should continue to be investigated.

In withdrawing the proposal requiring the tire-pressure device, NHTSA said that reliable devices are too costly -- about $200 per car -- while less-costly devices are too inaccurate to justify their use.

The NHTSA said it would consider an information program to alert consumers about tire pressure. CAS director Clarence M. Ditlow, however, said this step is inadequate now that gasoline stations no longer check tire pressure.

Contending that the reliable device would cost no more than $50, Ditlow argued that the NHTSA at least should continue studying its feasibility.