A Prince George's Curcuit Court judge yesterday ordered the county to place on the ballot this November a controversial charter amendment that could change the size and makeup of the county council.

The council voted 8-3 last week to drop the referendum from the ballot after the county elections board reported that petitions used to collect the necessary 10,000 signatures were not notarized.

But Circuit Court Judge Robert J. Woods ruled after a four-hour hearing yesterday that the council had no authority to keep the measure off the ballot once County Executiver Lawrence J. Hogan reported to the county board of election supervisors that it carried the necessary signatures.

"When he certifies that to the election board, the judge annmounced in court, "then the election board must accept it and put it on the ballot."

The referendum question would trim the council's size from 11 to nine members, all of whom would run from districts. The council now has six at-large seats. The measure was proposed by a group of Republicans, including Hogan, as well as several maverick Democrats.

Last week's council decision prompted the group to sue to have the referendum placed on the ballot.

John R. Barr, a lawyer hired with county funds to defend the council, and Ronald A. Willoner, counsel for the election board, both said they were unsure whether they would appeal Woods' decision.

Barr was hired at $75 per hour to represent two members of the council after County Attorney Robert B. Ostrom concluded he has an "ethical problem" doing so himself. Ostrum had told the council before last week's vote that it lacked the authority to drop the referendum.

Ostrum also said the county probably would not continue to pay legal fees if there is an appeal.

But council member Ann Landry Lombardi, who voted to drop the measure, said she doubted anyone on the body would pursue the matter further. "No one's going to appeal it," she said.

During yesterday's hearing, Barr argued that the referendum should be dropped because the sponsoring group had failed to notarize its petitions and prove that more than 10,000 of signatures were authentic.

Under questioning by the judge, Barr conceded that providing such proof would place on referendum sponsors "the impossible burden of bringing 10,000 people to court, and testifying it was their signature."

Using those criteria, asked Woods, "We wouldn't have many initiatives, would we?"

The decision, said Democratic State-Del. Timothy Maloney, one of the question's sponsors, "had restored law and order to the county." Now, added Maloney, "the council should start dealing with the merits of the question."

In an effort to counteract the refereendum the council, which consists of 11 Democrats, last month placed two other questions on the November ballot that deal with the council's composition. One would reduce the body to nine members, while the second would keep 11 council seats but make other modest changes in the current law. Council elections will be held in 1982.