Parents attempting to update their details with Centrelink to access the Turnbull government’s revamped childcare subsidy have complained the site has been frequently unresponsive over the past few days.

The site was shut down over the weekend for “scheduled maintenance”, just as the Coalition’s highly anticipated reforms to childcare rebates took effect on July 1.

IMPORTANT INFO: We're working hard to fix intermittent issues currently impacting Centrelink online accounts and Express Plus Centrelink mobile apps. We’re sorry for any inconvenience. If your business isn’t urgent, please try later. — Centrelink (@Centrelink) July 2, 2018

But on Monday and Tuesday many users were still unable to log in, prompting the agency to apologise for the “intermittent issues” and extend deadlines for support recipients trying to declare their weekly incomes.

Some users also reported extremely long wait times on hold, as more and more people gave up on the website.

SBS News understands some users are successfully logging in on Tuesday afternoon, but Centrelink has conceded many are still struggling.

“We’re working hard to fix intermittent issues impacting... mobile apps and Centrelink online accounts,” the agency wrote on Twitter at 2pm on Tuesday.

If you need to report your income, we’ve extended the deadline for this to 8pm AEST, so please try later today. — Centrelink (@Centrelink) July 2, 2018

“It’s a busy time, so if your business isn’t urgent, please try again later. We're sorry for any inconvenience.”

A spokesperson from the Department of Human Services acknowledged that some people had experienced intermittent issues when accessing Express Plus Centrelink mobile apps and Centrelink online, apologising for the inconvenience.

The issues were not related to the Child Care Subsidy, the spokesperson told SBS News.

The Coalition’s reforms to childcare payments took effect this week, replacing two previous schemes with one means-tested payment.

The government has spent months urging parents to update their details with Centrelink before the July 1 deadline, but around 200,000 families who were registered under the old system were yet to do so.

The new subsidy allows parents to claim government support on an uncapped number of hours.

Families on the lowest incomes will receive the highest level of subsidy, with 85 per cent of their childcare costs covered, while families in the highest income bracket will have just 20 per cent subsidised.

Recipients also have to satisfy an “activity test”, proving that both partners are working, studying or volunteering.

Families who earn a combined income above $350,000 are not eligible at all.

Education minister Simon Birmingham has threatened to name and shame childcare providers that opportunistically raise their prices to absorb the new subsidies.

“We will be monitoring the system closely,” Mr Birmingham said, speaking at a childcare centre in western Sydney on Monday.

“If there are providers who do the wrong thing then we will, of course, act to make sure that they are identified and they are held to account for doing so.”

Labor has criticised the rollout of the scheme, with around 200,000 families yet to switch their details by the July 1 deadline.

Those families could miss out on payments in the coming weeks, but the government has flagged “transitional arrangements”, including back-payments.