Chief Constable Simon Byrne has said people will "notice a change of police style" after the PSNI were handed new powers to battle the Covid-19 pandemic.
From 11pm on Saturday, officers have greater authority to enforce the closing of certain businesses and venues, require people to stay at home, enforce social distancing and stop all public gatherings of more than two people.
Anyone who repeatedly fails to comply with requests to disperse could face fines of up to £960.
The measures also provide for fines up to £5,000 for businesses not adhering to the new rules around closures and implementation of social distancing practices.
First Minister Arlene Foster said that while the new powers are "extraordinary", we are living in "extraordinary times".
Deputy First Minister Michelle O'Neill added that the Executive will use "every power" to ensure people stay at home so lives can be saved.
Mr Byrne said the PSNI has no desire to use the emergency policing powers but "it is right" that they can in order to enforce against those who disregard the measures.
Police will now target tourist locations and local open areas to encourage people to adhere to the new regulations.
On Sunday officers were spotted at locations including Castlerock beach and Murlough Nature Reserve.
Mr Byrne explained that the new dispersal powers will be used in a four-phase approach:
"We will only do this when it is absolutely necessary," he added. "Each and every one of us has a personal responsibility to follow the NI Executive regulations and do everything we can to stop the spread of Covid-19.
"Officers will apply their discretion and will ask questions to establish individual circumstances.
"We will instruct people to return home if they do not have a reasonable excuse to be out of their house.
"From today the public will also notice a change of police style and approach at tourist locations and local open areas to encourage people to adhere to the regulations.
"Our aim is to encourage and support the public to fully comply with these necessary restrictions."
Dr Tom Black, the chair of the British Medical Association in Northern Ireland, said it was vital that everyone followed the basic guidelines.
"The more social distancing, the more isolation we have, along with more hand washing - these things are in many ways more important than with other measures in regards to other things, like PPE to use an example," he said.
"To keep the community spread down we need to bring in all these measures.
"Most people will be sensible and only a minority will be stupid but I think that having sanctions for a stupid minority is what we do in our society. But most people will be sensible and won't have any problems with this."
Elsewhere, speaking on Sunday Politics, Agriculture Minister Edwin Poots said fines can be increased if a person is "grossly misbehaving".
"The law is now there and it'll be for the police to enforce that law," he said.
Communities Minister Deirdre Hargey added: "These are unheard of steps that we have had to take and obviously our approach to this pandemic has to be one around saving lives."