A record number of COVID-19 tests were conducted at the EPIC site on Monday and Tuesday, with a higher daily total than any day since the pandemic hit.
More than 1470 negative tests were returned in the past 24 hours, marking the third consecutive day with more than 1000 tests in a 24 hour period across the ACT.
There have been long lines of residents flocking to get tested this week, some facing wait times of almost five hours.
The ACT government said wait times had reduced on Wednesday with a two-hour wait at EPIC and 460 tests conducted as at 3pm and a one-hour wait at Weston with 260 tests conducted.
Staff numbers were doubled at both the EPIC and Weston Creek site early this week to help cope.
The government has resisted opening another facility, saying it was more efficient to boost staff numbers at existing sites.
"We're grateful to Canberrans for their patience at this busy time. Staff are doing everything they can to get everyone tested quickly and safely," an ACT government spokeswoman said.
She said demand had declined on Wednesday and late Tuesday.
"This is in line with typical patterns in our testing clinics after an outbreak interstate, where the first day or two are very busy before demand begins to drop off," she said.
"Should the COVID-19 situation in the ACT change so that increased demand is sustained over a longer period of time, we have identified options to increase capacity, including additional sites, to ensure we can maintain high testing levels to keep Canberrans safe."
The EPIC drive-through site has extended opening hours until Sunday.
Gates open at 7am with testing to begin at 8am. Gates close at 5pm but any car within the gate at 5pm will be tested.
The Weston Creek clinic operates from 7.30am to 10pm.
