Ending two days of heated testimony on Sen. Edward W. Brooke's "misstatement" about his muddled finances, Middle-sex Probate Judge Lawrence T. Pereira yesterday took under advisement a decision on whether to call a new trial on the senator's divorce case.

In an apparent reference to possible perjury charges against the senator for lying about his liabilities on a court deposition last year, Pereira said, "It may be necessary for me to take further steps . . . if the integrity of the court" was violated by Brooke's false testimony.

Brooke also faced a preliminary hearing in the Senate Ethics Committee yesterday on the same issue: the alleged misrepresentation of a $49,000 loan. Senate rules require disclosure of all loans over $2,500.

The Massachusetts Republican testified under oath on a May 1977 deposition that the loan came from a friend, liquor distributor A. Raymond Tye. He later recanted that testimony, saying $2,000 came from Tye and the rest from his mother-in-law, Teresa Fereri-Scacco.

He testified that he made a "mistake and a misstatement" about the source of the loan because of a "promise to his mother-in-law before her death last summer to keep family finances out of the divorce proceedings.

Pereira, whose ruling last year in favor of the divorce was scheduled to take effect next week, said if he determines there has been a "lack of a complete disclosure in a material sense either by confusion, errors or omissions I would be convinced the only remedy available is a new trial.

However, he warned Mrs. Brooke that a new trial would not necessarily "leave you in a better position than you are in today." Brooke's attorney, Robert McGrath, said that Mrs. Brooke has "ended up with 70 percent of his combined assets" and that a larger settlement would "just about wipe out any assets Sen. Brooke has."

A new trial like last year's highly publicized acrimonious proceedings could be politically detrimental to Brooke, who is campaigning for re-election to a third term.

The attorney for Brooke's wife, Remigia, said in closing arguments in yesterday's pretrial hearing, "the taint of misrepresentation, non-disclosure and fabrication to this court stretches credibility beyond a reasonable doubt."

At one point, stopping McGrath in mid-sentence, the judge said Brooke's financial statement was in "substantial error . . . why do I need to go beyond that?" in determining if a new trial is warranted.

"Because he wasn't misleading anyone in any substantial way," McGrath replied. "There was only an error in who he owed the money to, not how much."

Under tough cross examination by attorney George Ford, Brooke said that the $49,000 figure represents one-fifth of his liabilities.

The judge said he will not change the settlement agreement without a new trial. "I will not modify it, add to it, amend it or delete from it. If that is suggested as a possibility, I reject it," he declared.

Brooke's accounts are being audited by the Massachusetts tax department.