"Let's keep Singapore healthy", the yellow and black robodog named Spot said in English as it roamed around. "For your own safety and for those around you, please stand at least one metre apart. Thank you", it added, in a softly-spoken female voice.
Despite the niceties, breaches of Singapore's strict lockdown rules can result in hefty fines and even jail.
Another robot, in the shape of a small car, has been deployed at a nearby reservoir to warn visitors "not to loiter" and that "gatherings are not allowed".
The authorities behind the latest trial - the government technology and cyber security agencies – said in a statement that Spot could better cross rough terrain in parks and gardens.
Spot is fitted with cameras and analytics tools to estimate the number of people in the park.
Authorities said the cameras would not be able to track individuals or record personal data.