Police have warned they are cracking down on drug-taking partygoers after arresting 29 people and seizing almost 300 ecstasy pills and other drugs at a dance party in Sydney’s west.

About 3,000 revellers attended the Transmission Dance Party, which started at 9pm (AEST) yesterday at Sydney Olympic Park.

Police targeted dealers by using drug dogs outside the venue to nab any revellers trying to take illicit substances inside.

One of the people charged with supplying drugs was an 18-year-old man who allegedly had 55 ecstasy pills in his possession.

Another man, also 18, was charged for possession and supply of 42 ecstasy pills.

The 29 arrests resulted in more than 40 drug supply and possession charges.

Flemington Commander, Superintendent Alf Sergi, today told reporters the operation had been “very successful” and warned partygoers that police would be as much a fixture at upcoming parties “as the loud music and crowded dance floor”.

“We’re going to be very, very proactive in targeting these partygoers and the illegal activities associated with these parties,” he said.

“We have to be crystal clear to these people out there.

“We’re not going to tolerate drug use and drug activities because it’s very harmful to members of the community.

“They have to understand that,” he said.

“That’s our primary goal.”

Supt Sergi said he wanted to reinforce the point that party drugs were not only illegal but they could kill.

“We will not let go in our relation to a stand on these issues because they are very, very dangerous for the community,” he said.

“With young people the message is hard to get through but we will persevere and be relentless at it.”