A man has allegedly bitten a police officer on the leg while being arrested over the alleged sexual assault of a woman, NT Police said.

In a statement, NT Government crime marketing manager Sita Bacher said that just before 4am Tuesday, police patrolling an area near an unidentified service station in Katherine, found the woman who told them she had been sexually assaulted.

Ms Bacher said police searched the nearby area and found a 23-year-old man, who allegedly bit an officer on the leg while he was being arrested.

Police provided no further details.

The man remains in custody and is expected to be charged later on Tuesday.

On Monday NT Police called for anyone with information about a woman being assaulted by an unknown man near the Katherine Information Centre on Friday to contact them.

In a statement, police said they located a woman near the info centre around 11pm on Friday night, who told them an unidentified man had assaulted her. But police did not say if the assault was sexual in nature, and provided no description of the suspect.