However, as soon as the website opened this morning, it crashed under demand.
National Party immigration spokeswoman Erica Stanford said the website issues were not good enough given the backlogs already and issues around migrants already having left the country and those split by the border closure.
"What makes matters worse is that Immigration New Zealand knew this was likely to happen, as evident by the fact they asked immigration advisers to not submit all their applications on the first day.
"Rather than making desperate pleas to immigration advisers, the Government and the Immigration Minister should have had a plan in place that would stagger applications over time to ensure this didn't happen."
Immigration New Zealand general manager Geoff Scott said there had been a connectivity issue, affecting some users.
By mid-afternoon 890 applications had been successfully submitted, and 1400 more were in process.
The technical issue was being addressed but Scott said those who hadn't applied yet should wait until it was fixed before applying.
"We want to remind applicants that they have plenty of time to apply for their 2021 Resident Visa, with applications open until July 31, 2022.
"We encourage all applicants to take their time with their application and to make sure they have all the required documents and evidence they need to submit their application.
"This will reduce the time it takes for us to process applications as we will not need to request further information from applicants."
Before the website launch, Immigration Minister Kris Faafoi said they had been expecting high demand in the first few weeks, with lots of people wanting to submit their application early, but they asked people to be patient.
"We recognise that some of these individuals have been waiting for residence for a long time and are eager to get their applications in quickly, but they have plenty of time to apply."
It's estimated about another 150,000 migrants could be eligible for phase two, which opens from March 1, 2022.
Applications for both phases will be open until July 31, 2022. The Government has committed to processing the "vast majority" within 12 months.