In a statement the Metropolitan Police said patrols would be increased, including near drinking venues during the evenings, where breaches of regulations were "more commonly recorded".
The policing plan was unveiled on Thursday after the government earlier announced the alert level in London would be raised from "medium" to "high" from midnight on Friday.
The Met said it would use enforcement of the regulations - primarily through fines - only as a last resort.
Deputy Assistant Commissioner Matt Twist, Met lead for Covid-19, said: “This is a critical moment in London’s fight against this deadly virus and over the coming weeks I know the vast majority of Londoners will make the right decisions in order to keep themselves and their families safe.
“Frustratingly, we have seen a small number of dangerous and reckless breaches of the regulations and as the alert level in London increases, we are adopting our policing approach.
"Communities across London can therefore expect to see an increase in our efforts to deal with the most deliberate, harmful and flagrant breaches of regulations.
"We will not hesitate to take action against those individuals or businesses who put people at risk.
“As we move into this new phase of heightened alert, I would urge people across the city to work with us. By each of us being responsible, we can help minimise the transmission of the virus and help keep London’s most vulnerable communities safe from harm.”
Tier 2 rules mean people must not meet with anybody outside their household or support bubble in any indoor setting, whether at home or in a public place.
People must also not meet in a group of more than six outside, including in private gardens, and members of the public are being urged to reduce the number of journeys made on buses, trains and tubes.