Nearly 600 Ministry of Social Development (MSD) staff have been told their positions are being axed, chief executive Peter Hughes said today.

All up, 590 jobs would be disestablished but a further 360 new roles had been created. As well, the ministry already had some vacancies it hoped affected staff would fill.

"The worst case scenario is 200 redundancies but I'm confident that we will do better than this," Mr Hughes said.

"Final numbers won't be known until we've completed the process over the next month or so of re-confirming people into roles and re-assigning people to new but similar jobs."

All those whose positions were affected had been spoken to in the past few days, and all ministry staff were told of final structure changes today. All changes were expected to be completed by early August.

"We are focusing on moving our people into roles in the ministry that will achieve our overall goal of boosting the frontline and streamlining our operations," Mr Hughes said.

The 590 jobs include 80 positions at Child Youth and Family (CYF), with 12 administration service centres to be closed and a team of 18 child abuse education social workers to be cut.

However, CYF head Ray Smith said 12 new social worker positions to support foster families had been created, and new centralised administration roles established.

Social Development Minister Paula Bennett assured the public there would be more frontline social workers than previously, despite the cuts.

"I think where we're at is we want everyone out there talking about child abuse and we're moving that across a range of roles," she said.

"We've got vacancies in Child Youth and Family right now. We want those social workers (whose jobs are affected) to be applying for them so that we can move them into those roles.

"I think we're going to be having more social workers on the front line."

Ms Bennett said access to care and service would not be compromised.

"I can absolutely assure them that the concentration is on frontline staff, on social workers that are working with those people that need it most, and that's where this Government is putting their priorities."

Prime Minister John Key said the priority for social workers should be frontline social work.

Savings made by closing the administration service centres and cutting the team of child abuse education social workers would fund extra frontline social workers, he said.

"In other words, some people who were employed to promote awareness are being replaced by a much greater number employed to promote prevention.