Police say a drug lab supplying millions of dollars worth of cocaine and methamphetamine was hiding behind the facade of a rural home in Yass, an hour north of Canberra.

Key points: Three Australians and one Spanish man are charged with drug manufacturing and supply

Three Australians and one Spanish man are charged with drug manufacturing and supply Police raided a Yass home yesterday and found the large drug lab inside

Police raided a Yass home yesterday and found the large drug lab inside Officers seized 30kg of cocaine, worth $9 million

Four men were arrested at a Yass hotel yesterday, before police searched a home in the area and found a large scale drug lab in the house and a neighbouring garage.

During their search officers seized 30 kilograms of cocaine, precursor chemicals used to make drugs, cash in both Australian and European denominations and several mobile phones.

The raids were the culmination of an investigation that began in April.

Four men will face Goulburn local court today. ( Supplied: NSW Police )

Three of the arrested men were Australian citizens, who appeared in Goulburn Local Court on Wednesday morning.

Jordan David Stephens, 19, David Quang Dung Pham, 35, and John Capistran Le, 40, were all denied bail.

Also denied bail was Esteban Ricardo Forero Gomez, a 25-year-old Spanish national.

All four had their cases adjourned until August 28.

All of the men have been charged with manufacturing and supply of large quantities of prohibited drugs.

Police said chemical operations officers would continue working to dismantle the drug lab, and that several items had already been seized for forensic examination.

Detective Acting Superintendent Jayne Doherty said the strike force responsible for the raids would continue its investigations.

"We've seen the effects of these prohibited drugs in regional areas and how it can wreak havoc on communities," she said.

"We are committed to removing these toxic substances from our streets, no matter where in NSW drug peddlers seek to make a profit off others' misery."

She said the investigation was triggered by information from the community, and encouraged anybody with information to contact Crime Stoppers.