The figures previously included specific information about the number of domestic incidents police responded to, but the most recent set, released last month, did not.
At the time, police said new processes for recording information about family events meant the figures would not have given a meaningful comparison with previous results.
Women's Refuge has raised concerns about the new system, saying that without specifically including a family violence category the extent of the problem could not be properly measured.
Deputy Police Commissioner Mike Bush said family violence statistics would still be recorded and made public, but the way incidents were counted would change.
"Statistics around family violence are complex. Our official statistics are the result of counting each offence as it is recorded. There is no offence of 'family violence','' Mr Bush said in a statement.
"People are charged with offences such as male assaults female, grievous assault, sexual assault, harassment and many others. All these offences can be `family violence' but in some cases they are not because the crime doesn't involve people who have a relationship with one another.''
Although the previous data gave a good indication of family violence levels, police said the changes would allow for more accurate results about the actual number of offences and were in line with international best practice.
Labour police spokesman Kris Faa'foi said he wanted to be sure there was a way of tracking family violence levels and the police had not made it clear whether that would be done.
"Without that we won't be able to tell how we're doing in terms of progress of bringing down family-related violence, and that's what the likes of the Women's Refuge and other agencies need to know whether what they're doing is working.''
Mr Faafoi also questioned the reason for the change, suggesting the move might have been motivated by politics.
"I fear that there's something political behind this, that this is something that's been done so that in a couple of years time the Government can say `haven't we done a good job of reducing family violence' by changing the way the stats are collected and reported.''
In a statement this afternoon, acting Police Minister Chester Borrows stood by the change, saying a record amount of information about family violence was being collected.
"These changes follow international best practice - they are not hiding the figures, they are about improving police response to domestic violence.''
