An under-2-year-old is admitted to hospital every week because of abuse, and more than a third of them were admitted because of shaking, a select committee has heard.

Social Development Minister Paula Bennett told the social services select committee yesterday awareness campaigns, such as "never, ever shake a baby", were having a positive impact.

On average 61 under-2s were admitted to hospital because of abuse every year for the three years to 2007-08, and of those 23 had been shaken.

Ms Bennett said there were difficulties interpreting the figures because different agencies had different methods of tracking and recording the numbers.

"We're not under any illusions around the complexity and the big job it is to reduce the number of children who are abused or neglected, and it's going to take a concerted effort across more than just one department," Ms Bennett said.

She was quizzed about the large increase in Child Youth and Family notifications, which had risen from 40,000 a year five years ago to 125,000 projected for this year.

Ms Bennett said this was mainly because of campaigns, which had led to more family members and neighbours reporting cases of domestic violence.

"Some of it is just about raised awareness, and there can be more than one notification for one child."

CYF chief executive Ray Smith said the department had greatly improved response times.

"When these awful tragedies happen, it isn't usually because someone hasn't turned up in the required response time-frame. They usually happen in the course of many months of work where things go wrong in the case, as opposed to not being able to get to the case."

As at March 2010, CYF was completing 95.5 per cent of investigations on time, and 98 per cent of family group conferences were held on time.