Technical problems on its My MSD website today are unrelated to a large number of log-in attempts, the Social Development Ministry says.
Today is the first day beneficiaries can use a tool on the site to check how much they are owed because of bungled payments.
Earlier this year it was revealed an automatic payment error meant 49,000 current and past beneficiaries were underpaid or overpaid.
The mistake totalled millions of dollars.
About 22,000 current clients are to receive a total of $14 million in reimbursements. All the payments are expected to be made by the end of the year, accompanied by a letter of apology from the Ministry.
The Ministry expects the website to be operational again soon.