A person found with self-sealing plastic bags less than two inches tall or wide faces a fine which could be as much as US$1500 (£745).

The fine applies to those who know or suspect that the bags would be used in the drug trade.

"I can find bags like these at all times in my ward," said Alderman Bob Fioretti, the man behind the measure.

"These are literally all over the parks."

At the hearing to approve the measure, concerns were express that innocent people would suffer under the measure -- it was pointed out that spare buttons sold with clothing often come in small self-seal bags.

"I want to make sure we have language in place so that innocent people don't get caught up in these situations," said Alderman Walter Burnette.

Alderman Fioretti highlighted the clause in the law that is supposed to target only those who 'reasonably know' that the bags are used for drugs.

"You need to have the criminal intent there, and that's clearly stated in the ordinance," said Fioretti.

He added that 'drug dealers will have these alongside of them -- they won't be having buttons with them in these bags.'

"When we look at the numbers in our parks that you can find in one Sunday, then you know, we're not having garment dealers using these bags."

Chicago Police Lieutenant Kevin Navarro, a gang and narcotics supervisor, said that police would not be stopping people to search for the bags specifically.

"This would be something we would add onto the drug offence," he said.

Navarro is hoping to use the measure against businesses that cater to the drug trade.

"We have a few businesses on our radar right now," said Navarro.

"They know what's up."

"They know what they're doing."

"This will be a very important tool for us to go after those businesses."

The measure will now go forward for ratification by the full city council on March 12.