Melbourne's Crown casino is in crisis after discovering its tables had been flooded with a fortune in counterfeit gambling chips.

Casino bosses were scrambling to check the authenticity of a staggering $13.7 million worth of $1000 chips after near-perfect fakes were detected Thursday.

Crown admitted it had so far found $36,000 in fraudulent chips, the Herald Sun reports.

To limit the damage, the casino resorted to changing the color of its $1,000 chips to a different shade of blue.

A hunt for those behind the fraud has begun.

A gaming floor worker raised the alarm as she handled one of the chips in the high-security counting room.

Crown officials admitted they had no idea how long the fraud had been going on or how much they had lost.

"While doing routine checks, one of the officers detected what appeared to be fake $1,000 chips. As a consequence of that, we recalled all of the $1,000 chips from all of the tables," casino spokesman Gary O'Neill told the Herald Sun.

O'Neill said the fakes were of a "reasonably good quality."

"We have checked all of them and we have found 36 fakes," he said. "I'm not saying it's not a problem ... but we have reissued a completely different chip."

Gamblers at Crown were kept in the dark Thursday as the $1,000 chips were gradually swapped for a different color.

Click here to read more on this story from News.com.au.