A federal judge here today extended the June 1 deadline for the removal of several hundred inmates from the Maryland prison system, which was found unconstitutionally overcroweded more than two years ago.

U.S. District Judge Alexander Harvey extended the deadline by 90 days, but warned that if the new Sept 1 deadline was not met, he would "take the drastic action of ordering the release of state prisoners" himself.

Under previous rulings, the state had been ordered to end "double-celling" -- the practice of placing two inmates in one cell at the maximum-security Maryland Penitentiary in Baltimore and the century-old House of Correction in Jessup.

Two federal judges had ruled in 1978 that housing two inmate in cells of 40 to 44 square feet "offended contemporary standards of human decency" and that the two prisons were so overcrowded that conditions represented "cruel and unusual punishment."

The state this week met the June deadline and ended the double-celling at the House of Correction when Gov. Harry Huges orderd the sentences of 110 prisoners commuted immediately.

But the state still must reduce by nearly 280 prisoners the population at the penitentiary in Baltimore to comply with the court order, according to Maryland Attorney General Stephen Sachs.

Hughes said that the state will continue its efforts to comply, but added, "I cannot say with certainty at this time that we can meet the court-imposed standards within the 90 additional days."

The state, which in 1978 received a lengthy extension of the original court deadline, had sought a 10 1/2-month extension of the June 1 date. State officials cited in particular construction problems which have delayed until next November the opening of a facility with 400 new prison beds. That facility had been scheduled to open June 1.

Harvey said in his opinion today that state officials have made "a good faith effort to comply with this court's decrees, although on hindsight it is apparent that they have not been as imaginative or resourceful in their approach to the prison overcrowding problem as they might have been."

Harvey said the state had relied too heavily on new prison construction to solve the problem, but noted that a recent effort to identify prisoners for early parole has been successful in cutting the population.

In May 1978, the state had been ordered to cut the population by 1,100 inmates and has now come within 300 prisoners of that goal, Sachs said today.

The attorney general said that along with the state's desire to make its prison system meet constitutional standards, there is yet another impetus to end overcrowding -- "the enormous expenditure of time and money" in fighting the court case.

The state has paid more than $100,000 in fees to attorneys representing the inmates who brought the lawsuit against the state and are considered paupers who must be represented at state expense, according to Sachs.