Police have warned organisers against going ahead with the Workers' Day march on May 1.
However, the organisers are insistent on going ahead with the rally, which they said had proceeded yearly without incident.
In a statement today, Dang Wangi district police headquarters chief Mohd Sukri Kaman said the decision not to allow the rally was due to the organisers failing to fully comply with the notice of gathering required by law.
"I have given a warning to the organisers not to go ahead with the rally as they failed to comply with Section 10(c) of the Peaceful Assembly Act 2012, which requires that they seek approval from the owner of the venues.
"Therefore, the organisers' application cannot be processed.
"If the gathering goes ahead, the organisers will face legal action under the Peaceful Assembly Act 2012 and other existing laws," Mohd Sukri said.