Detectives had placed Daniel Daquinta, 27, under physical surveillance as part of a three-month investigation that culminated in what they say is one of the largest ecstasy seizures in the territory's history.

Daquinta, who appeared in the ACT Magistrates Court on Tuesday, was followed by police as he drove from his mother-in-law's house in Latham to the top level of a car park at the Belconnen shopping centre. Two men approached the passenger side window of his Nissan Navara ute and had a conversation.

The men left, and police followed one to Braddon.

He allegedly told officers he had just bought $100 worth of speed from a man named ''Dylan''.

Later that day, police executed a drug warrant at Daquinta's residence in Latham. They found drug paraphernalia in three cars parked in the front yard and in a garden shed in the backyard.

A manual pill press was seized, as was 1.5 kilograms of a powder thought to be ecstasy, and 120 grams of suspected methylamphetamine.

Police told the court they feared Daquinta was working as part of a larger syndicate, and could not have afforded some of the items in his possession.

They said they watched for several weeks as people got into Daquinta's car, sat inside for a brief period and then got out.

They said Daquinta refused to be interviewed and his family did not wish to speak with police.

Daquinta applied for bail on Tuesday, but prosecutors opposed that. They argued he could interfere with the continuing drug investigation, commit further crimes to fund his drug habit, or abscond.

But Daquinta's barrister, Steven Whybrow, said that bail conditions could manage any such fears.

There was no real evidence to suggest he would commit further crimes, or leave the territory. If the courts waited for the investigation to be finalised, police would effectively be ''holding the cards'' in deciding when his client was released.

The bail application was adjourned for a week, to allow police to complete their investigation and alleviate concerns that Daquinta could interfere.

Police said they needed to speak with a long list of people identified in the three-month investigation, and were also waiting on test results to confirm the exact nature of the seized substances.

The case will be back in court on Tuesday May 28, when another bail application is expected.