Some people wanting to apply for visas through Immigration New Zealand's website before fees and levies rise on Tuesday have experienced problems accessing the online platform.
RNZ received reports of the system being down for large periods of time since Sunday.
Immigration New Zealand's director of online services Katy MacLeod said it was aware some people had experienced issues accessing its online platforms.
"We acknowledge that many of our customers will be planning to submit their applications today ahead of the fees and levies increase. We are working to resolve the issue urgently and apologise for the disruption."
In August, the government announced visa fees and levies would be going up to ensure the system was self-funding and more efficient.
Most international visitors applying for a visa or NZETA (New Zealand Electronic Travel Authority) need to pay a non-refundable International Visitor Conservation and Tourism Levy (IVL) to enter New Zealand.
That charge will increase from $NZ35 per eligible person to $NZ100.
Migrants applying for the skilled residence category will be charged $6450, up from $4290 currently.
Partners applying for residency will see their fees climb to $5360, up from $2750.
Student visas, meanwhile, will double from $375 to $750, while post-study work visas will jump from $700 to $1670.