Warrnambool police targeted four properties this morning and recovered prescription drugs, four marijuana plants, firearm ammunition, an amount of cash and jewellery.

Senior Sergeant Shane Keogh from the Criminal Investigation Unit said four Warrnambool men were in custody and assisting police with enquiries.

"It is anticipated that charges will be laid in due process," Senior Sergeant Keogh said.

Matured marijuana plants can be worth up to $5000 a plant.

Senior Sergeant Keogh said the warrants were a result of the operation, Dob in a Dealer, which began last week.

"We're extremely happy with the operation," he said.

"As a result of Dob in a Dealer this information has come through.

"We've removed some weapons and drugs from the streets of Warrnambool and hopefully it will be a safer place as a result of it."

Senior Sergeant said police would continue to target drug traffickers and users in Warrnambool, Camperdown, Hamilton and Portland and were calling on the public to provide any information they had.

He said as police received information, they processed and investigated the leads before executing warrants.

"That's what happened here," he said.

"As we get the information we'll process it and put it through.

"Obviously the aim is to remove drugs from the street.

"We will process the offenders and assess any of those users that need counselling or referral services."

Senior Sergeant Keogh said people who have contacted police with information in the past and have new information they think police may want to know about should call police.

"This is going to be a continued campaign so anyone with any information in relation to drug dealing or drug using please contact Crime Stoppers on 1800 333 000."

cquirk@fairfaxmedia.com.au