Human rights group Maruah had misrepresented the nature of a foreign worker rights forum to the owner of a venue they intended to use for the event, the police said on Monday.
In a media statement, the police said they were informed of this by the owner of the Ananda Bhavan restaurant in Little India.
The owner then cancelled the booking for the Monday event "of his own volition", the authorities added.
The event, titled "Foreign Workers, Justice & Fairness", was moved at the last minute to the Marketing Institute Of Singapore, located along North Bridge Road.
A police spokesman added that it had previously advised the public against organising any events in Little India that could "heighten emotions and cause concern during this period", so as to give residents and the Little India community the "space and time" to recover from the Dec 8 riot.
Responding to the police statement, Maruah said it had not misrepresented itself, and added that they were disappointed with the restaurant management's response to the police.
"We have correspondence with the restaurant on this matter, and have nothing more to add to this discussion," it added.
On Sunday, Maruah had cited "blatant harassment by the government against lawful and legitimate civil society activities" for the need to change the venue of its forum.
The restaurant contacted them only on Saturday night to say that they had decided to cancel the booking and give a refund, it added.
Ananda Bhavan chief executive Viren Ettikan told The Straits Times this decision was reached after the police visited them and mentioned the need for stability in the neighbourhood after the Dec 9 riot.
He thought the event was "for some charitable cause, or a discussion."
"Now the police are trying their best to ensure things are stable, we should as a business, ensure that everything is smooth, not add to any such things," he said on Monday.