Sussex Police has announced plans to axe 1,000 staff over the next five years.

Some 500 police officer positions will go, as well as an additional 500 staff.

The five-year plan aims to save £56 million by 2020.

The announcement, which follows the implementation of £50 million worth of cuts to the force over the past five years, was made at a joint press conference held by Chief Constable Giles York and Police and Crime Commissioner Katy Bourne.

Mr York said the force would continue to prioritise crimes "that cause the greatest harm to victims and the community".

But he said key to the success of the new model would be the public understanding a reduction of demand on officers on a day-to-day basis so that the force can continue to deliver core policing.

Mr York said: "My aim is to deliver policing more efficiently by embracing technology and multi-agency working, reducing costs and engaging with the public in a way that suits them and us better.

"It is only by changing the way we deliver our service that we will be able to maintain the level of public safety we have achieved in Sussex.

"It's absolutely paramount that we respond when people face significant risk and harm.

"I am starkly aware that there will be a lot of public interest in how this will affect them and I am also aware that some will experience a reduction in some parts of policing that are very dear to them."

Mr York said the force would continue to prioritise crimes such as harmful antisocial behaviour but that a radical change would not be introduced until he could be confident that the skills and technology were in place to deliver it successfully.

He continued: "The simple fact is that we can no longer respond to issues which would be more effectively dealt with by other providers or by working in partnership.

"An example is our successful street triage scheme which pairs mental health nurses with police in resolving emergency responses to those facing a health crisis and giving them a better alternative to police custody.

"It is this kind of thinking we need to apply across our business."

The model, which will be implemented in stages over the next four years, sets out local policing in terms of prevention and response and investigation.

Mr York said Sussex Police will collaborate with partners, including Surrey Police, to gain maximum benefits in terms of financial saving and maintaining good quality policing.

Other changes will include a resolution centre, staffed by officers, providing professional advice online or by phone to resolve issues at the initial point of contact, and more online services will be made available to report crime, a police spokesman said.

Officers will be equipped with mobile devices to easily access information and complete administrative tasks while out in the community, reducing the need for them to spend time at police stations, and police community support officers will have a wider range of skills and become more flexible so that they can focus on those most in need, he said.

More officers will also be trained to deal with a range of issues, reducing the need for specialist officers, and victims and witnesses will have an officer dedicated to them throughout their case, reducing the need for handovers.

Mr York said: "As part of the Serving Sussex 2015 programme over the last five years we have already made cost savings of more than £50 million, while still protecting our front line and delivering a quality service.

"Now we must trim further and to do so we have to look at our most significant area of cost - our people."

Sussex Police and Crime Commissioner Katy Bourne said that the ongoing challenge would be for the new model to maintain public confidence and reassurance while delivering an effective and efficient police service.

She said: "Everyone has a part to play in reducing and preventing crime.

"I will continue to work closely with the police, partners and the public to ensure we all take responsibility for keeping Sussex safe."

Forces across England and Wales are facing a 5% cut in government funding in 2015/16, an investigation by the BBC found at the weekend.

After 2016 they are expecting austerity measures amounting to hundreds of millions of pounds, although the precise level of savings will depend on the outcome of the general election.