New Zealand First says a steep drop in child abuse rates should set off warning bells across the social sector.

'A 12 per cent decrease of children abused is statistically unusual and has made us think twice about blindly believing the Government's results,” says Spokesperson for Social Development Darroch Ball.

'The Government's Better Public Service targets are only useful if they rely on independent scrutiny.

'The Salvation Amy's latest State of the Nation report showed that despite a fall in substantiated cases of child abuse or neglect the number of recorded offences rose 3.5% over the year to 30 June 2014.

'This is a record 5397 offences, 56% higher than in 2009.

'When questioned in the House last week Social Development Minister Anne Tolley was reluctant to say she had confidence in the accuracy of the figures and indicated the downward trend may not continue.

'How can her Ministry be confident in their Better Public Service results without a public independent audit of how they are achieving them? It's like a self-licking ice cream cone because the pressure to achieve targets on departments like Child Youth and Family could lead to manipulated outcomes.

'We are keen to remove any doubt that this sudden drop suggests a change in processes or softening of thresholds by Child Youth and Family.

'The only way the public can be confident in results set against Better Public Service targets is to ensure they are independently audited,” says Mr Ball.