The government of El Salvador is engaged in a campaign of "systematic political murder" that disqualifies it from continuing to receive U.S. military aid, two civil rights groups charged yesterday.

The Americas Watch and the American Civil Liberties Union called on the Reagan administration not to certify El Salvador for having made progress on human rights when that twice-yearly finding comes due next week. Certification is required by law for El Salvador to continue receiving military aid, which totaled $81 million this year.

State Department officials have said the administration will repeat its January certification that El Salvador is making a "concerted and significant effort to comply with internationally recognized human rights," keeping its military under control, promoting land reform and supporting free elections.

Aryeh Neier of Americas Watch said, "We believe that none of these four conditions have been complied with."

In a 272-page report detailing its findings of conditions in El Salvador, the groups charged that government security forces committed 2,829 political murders the first half of this year, a number it said "almost certainly grossly understates the extent of political violence."

The report also charged that the government uses its military "to terrorize the civilian population" so they will stop supporting guerrilla forces. It also has stymied land reform, the report said, and, in elections in March, "effectively excluded the opposition which reasonably feared that its candidates would be murdered if they campaigned."

In a separate report, the Lawyers Committee for International Human Rights warned that five National Guardsmen arrested for killing four American churchwomen in December, 1980, "may never be tried and punished." The report criticized both the U.S. and Salvadoran governments for refusing to explore evidence that higher military officials may have taken part in the murders.

The House of Representatives last week passed a resolution requiring President Reagan to certify that the Salvadoran government was making "good faith efforts" on that case. The Senate is expected to consider an identical measure this week.

The ACLU earlier this month called the administration's first certification a "sham," and officials conceded that their report probably would not prevent next week's certification.

But Neier said, "We do not think the battle is over if the president decides to recertify. It simply means the battle shifts to the Congress and the battle for public opinion."