Virginia's new corrections chief directed sweeping changes in the administration of the state's troubled prison system today and ordered strict new security precautions in all of the state's prisons, including hiring 132 more guards.

Newly appointed Corrections Director Allyn R. Sielaff announced the wide-ranging changes, including enhanced security steps and the demotion of several top prison executives, after a series of breakouts and disturbances that has left Gov. Charles S. Robb's administration reeling from criticism.

Sielaff issued the new orders hours after the state's third major escape in six months ended. An inmate convicted of two Northern Virginia murders was recaptured near the West Virginia border two days after he walked out of the front gates of a prison.

"We will be getting back to basics in an effort to prevent the kind of escapes and other incidents that have occurred recently," Sielaff said today.

Sielaff, who has headed prison systems in Pennsylvania, Illinois and Wisconsin, said he will divert $1.4 million from the corrections department budget to hire 132 new guards immediately. He also said the prison system will institute tougher security measures, more armed perimeter patrols and the installation of laser and seismic detection devices around the prisons to prevent escapes.

Some of the most far-reaching changes involve a major shakeup in the corrections department administration, which has been criticized by some state officials and prison watchdog groups as unresponsive to efforts to improve prison facilities and inmate conditions.

"Where the public has lost confidence in the department is where there continue to be escapes," said Sielaff in an interview today.

Three top administrators were reported demoted, including Robert G. Spann, deputy director of the adult prison system, who was given unspecified duties not related to prison security.

Several other administrators in key positions were given new duties as well.

The most stringent changes in Sielaff's proposals were aimed at prison wardens and other security officers at the prisons.

He canceled all vacations for wardens and other prison administrators indefinitely and demanded that a warden, assistant warden or security chief must be at every facility at all times when inmates are not confined to their cells.

"Wardens are to be out in the institution daily to assure personal contact with all aspects of the facility's operation," said the new directive.

"We want strong managers who will make people toe the line," said Sielaff. "We are telling people you can't sit in your offices, you've got to get out in the institution and not sit back and make assumptions that people understand their jobs."

Those changes are in response to pointed criticism from consultants who attributed the May 31 escape of six death row inmates from Mecklenburg Correction Center partly to the isolation of prison administrators from the daily operation of the maximum security facility near the North Carolina border.

Sielaff, appointed by Robb last week to the $62,000-a-year position after the resignation of Robert M. Landon, has earned the support of some of the most liberal prison advocacy groups during his tenure as head of other state prison systems As in Virginia, he took over the Pennsylvania and Illinois corrections departments during periods of intense controversy and turmoil.

The 53-year-old prisons chief said today his new orders are intended to correct security lapses such as the one that allowed a murderer-skyjacker from Northern Virginia to walk past a prison guard and out an unlocked front door of the Bland Correctional Center near Roanoke Wednesday night.

Bryce Matthew Tuller, 31, was stopped by state police about 3 a.m. today as he emerged from a mountainous area and began walking along Interstate Rte. 77 near the West Virginia border.

State police said Tuller offered no resistance and told police he was cold and hungry from two nights in the woods.

Tuller was serving two life sentences for the murder of a bank manager and a policeman in a 1972 robbery attempt. He also was convicted of hijacking an airplane to Cuba.

Although a flurry of consultant and special committee reports harshly criticized the state prison operations, relatively few of the recommended changes have actually been instituted.

Sielaff said he began implementing many of the changes yesterday. "We're in an urgent situation that needs attention," he said, adding "We had to shape up things very quickly. We're not waiting days and weeks."

Top administrative aides who were promoted as well as those who were demoted were ordered to report to their new jobs this morning, only hours after the decisions were made