The number of sexual assaults and related offences rose to 355 last year from 246 in 2013, according to the latest data from Statistics New Zealand.
But acting Southern district commander Inspector Steve McGregor ascribes the surge in offences as evidence of the public's trust and confidence in Southern police.
''We are mindful that, in the past, victims of sexual assault have been reluctant to report this crime due to a number of factors,'' he said.
''However, a lot of work has been done by police in this area to improve our ability to investigate these crimes.
''Police are confident that the increase in reported cases of sexual assaults and related offences shows the increased numbers of the public who have the trust and confidence in us to report this crime, and the excellent support available to victims.
''Police treat such incidents as a high priority and we continue to encourage victims of such crimes to report them and receive the support they need.''
As of April 1, only 57% of those reported offences were resolved.
But the district had increased staff investigating sexual assault cases during the ''past few years'', Insp McGregor said.
''In addition to this, the district continues to look for opportunities to have greater collaboration with other government agencies such as Child, Youth and Family to enhance service to victims in such cases.''
When asked about the general nature of the offences and whether offenders were known to victims, police said that information would have to be requested under the Official Information Act and was ''currently unavailable''.
The number of acts intended to cause injury also rose last year to 2636 from 2469.
When asked if the district was becoming increasingly violent, Insp McGregor said: ''Police are continuing to work within our communities and with partner agencies to make Southern district the safest place to work and live.
''The overall trend in crime in Southern district continues to go downwards. However, over the coming months police will work towards identifying areas where we can intervene in serious crime to help this trend continue.''
Insp McGregor said he was confident the Southern district was a safe place for women.
''We cannot forget that violent offending of this nature is not just directed towards women,'' he said.
''As such, Southern district police continue to work towards making our district the safest place to live and visit in New Zealand, no matter your gender, age or background.
''Despite the rise in reported cases, Southern remains a safe community to live in and visit, but we will continue to work hard at reducing victimisation across all crimes areas, with an emphasis on the safety of our community.''
Total offences in the Southern district - which covers Otago and Southland - fell 4.3% to 19,447 last year, down from 20,326 for the year before.
Police would take multiple approaches to tackle sexual violence, including supporting victims, educating communities and partnering with other agencies in the area, he said.
''We are increasing our focus on opportunities to deal with family violence incidents across the district and interagency partnerships working towards broad, as opposed to singular, solutions will be a big part of this,'' he said.
''The community can play a significant role in assisting police in this area by remaining vigilant to cases of family violence and seeking advice from police when there are concerns.''
Police also continued to look for chances to cut harm from alcohol and drug abuse, which was often linked to crime, and this involved gaining the support of all sectors of the community, he said.
