Uptake of the expanded scheme which more than 560 small businesses have signed up for, has far exceeded the expectations of ACT Business Minister Tara Cheyne.

As it launched on Wednesday the website was "under maintenance" for several hours, which an ACT government spokeswoman said was likely due to the high volume of traffic on the site.

"Our priority is stabilising the platform and ensuring its reliability. We are actively monitoring the platform and addressing the issues as they arise," she said.

The website appeared to be working for most users on Wednesday afternoon.

As of Wednesday evening, $140,960 of the $2 million ChooseCBR scheme had already been spent.

The scheme was first trialled in December but only $310,000 of the $500,000 available was used over the three-week period.

"We are pleased that Canberrans have wholeheartedly embraced ChooseCBR and are making use of their vouchers to support small business," Ms Cheyne said.

"The popularity of the scheme among businesses and customers alike has exceeded our expectations. Regrettably, we have experienced intermittent issues with the system on this first day.

"I acknowledge this has been frustrating and regret the inconvenience caused. I want to stress my thanks for the community's patience and support as we work to resolve these issues."

The landing page of the ChooseCBR website on Wednesday morning and part of the afternoon said the site was being upgraded.

"We are upgrading the Choose CBR website. The site will be unavailable for a short time while work is carried out," a statement on the website read.

"We apologise for any inconvenience, please check back soon."

The vouchers must be accessed online. Those with a smart phone can sign in to the website and show the QR code to be scanned at retailers. There is not an Apple or Google app for the vouchers.

During the December trial, the website also experienced teething issues on its first day, as users reported they struggled to log onto the website.

Ahead of the launch, Ms Cheyne said she hoped the overhauled scheme would work better for small businesses, as the eligibility criteria had been extended and the discount amounts were greater.

The scheme will offer discounts of up to 50 per cent, subsidised by the ACT government. Customers get $10 off when at least $20 is spent, $20 off when at least $40 is spent and $50 off when at least $100 is spent.

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