A 60-day nationwide state of emergency, announced last night, is the sharpest measure undertaken yet by Peru's democratic government to expand its efforts to control the leftist Sendero Luminoso guerrillas.

The measure suspends constitutional guarantees of freedom to travel and to hold meetings, as well as protections against unwarranted search, seizure and arrest for all of Peru's 18 million inhabitants. It follows a series of bombing attacks against coastal cities attributed to the guerrilla organization, whose name means Shining Path.

The attacks, aimed primarily at power pylons and hydroelectric facilities, culminated Friday night in a blackout of this capital city. Police here have reported more than 100 suspects detained in connection with Friday's attack, which included the firebombing of one of the country's largest factories, the Bayer synthetic fibers plant.

For the elected government of President Fernando Belaunde Terry, the recent guerrilla attacks have compounded the strain of serious flooding in northern Peru, a severe drought in the south, and a financial crisis that has triggered inflation running at an annual rate of more than 150 percent this year.

The government also announced that it was initiating a "plan of internal security" to protect Lima and other cities from further guerrilla attacks. According to government officials, the plan will be coordinated with the joint command of the armed forces.

So far, most of the fighting between the government and the Maoist Shining Path has taken place in the central Andean region, 250 miles southeast of Lima. Last December, Belaunde placed that department of Ayacucho and two adjoining provinces under the political and military command of the Peruvian Army.

Since then, fighting in Ayacucho has escalated dramatically. Military sources report that government forces have killed 400 guerrillas during the last four weeks, nearly doubling the number of guerrillas reported killed since they surfaced in 1980.

However, officials in Lima have said privately that many of the deaths are of peasants caught in the crossfire. Remote areas of Ayacucho have been virtually closed off to the press by the local military command.

The declaration of the state of emergency, according to some political analysts in Lima, is a sign that the government feels its ability to manage the guerrilla problem is slipping.

The suspension of constitutional guarantees caused Belaunde's own party, Accion Popular, to cancel a rally called "Democracy in Action" that was scheduled for Wednesday. Belaunde was reelected president in 1980 after a 12-year interlude of leftist military rule that ended his first term. Belaunde spent most of those years in exilein Washington.

The Associated Press quoted Interior Minister Luis Percovich as confirming reports that the guerrillas had moved into the Andean region around Cerro de Pacsco copper mine, 190 miles northeast of Lima. He said civil guards had been sent to the scene.

[On Monday, the Maoists struck north of Lima, in the coastal area, for the first time, dynamiting power pylons.]