Montgomery County police have opened a new investigation into alleged sexual misconduct by police officers after a second woman reported that she has had sexual liaisons with more than 25 on-duty police officers.

The woman also told police investigators that she has had sexual relations with another 25 off-duty police officers in the county's 750-member department, sources inside the department confirmed yesterday.

Her charges were made to police investigators late Monday, nearly a month after a fomer county resident now living in Michigan alleged that she had used a citizens band radio to arrange sexual liaisons with several on-duty county police officers.

The second woman went to the department's internal affairs unit late Monday and identified pictures of more than 50 officers with whom she said she has had sexual relations over a two-year perod.

She did not, however, file formal charges against the men.

"She made some allegations, that's the height of it," Maj. Donald E. Brooks, acting police chief, said yesterday.

One of the men named was an officer in the internal affairs unit. Brooks temporarily transferred the officer out of the unit Tuesday to another section of the department.

Brooks said yesterday he ordered the transfer because "I'm interested in not compromising the investigation." In December, three internal affairs officers were assigned full-time to the investigation of the allegations by the former county woman now living in Michigan.

Their work was extended to the second woman's allegations this week, put police spokeswoman Nancy Moses said that the two investigations are being conducted separately.

"We don't know if they allegedly involve the same men or whether the women knew each other," Moses said.

Although police would not identify the accusers, the Montgomery Journal reported yesterday that the second woman is a nurse working in a county nospital. The Journal reported that because of the serious nature of the charges, it had asked the woman to submit to lie-detector tests.

The Journal said that the woman voluntarily agreed to the tests. She was asked several questions about having "oral sex' with county police officers and answered the questions "truthfully," according to Walter F. Atwood, a Hyattsville polygraph expelt who adminstered the tests, the Journal reported.

The newspaper also said that the woman identified the officers as assigned to the Silver Spring, Wheaton Glenmont and Rockville stations. She told the Journal that some of the alleged liaisons took place in police cruisers.