A rushed law change last year saw a number of people's benefit payments wrongly suspended because officials could not keep up with the paperwork, the Social Development Ministry has confirmed.

It's the second major error identified due to the law passed under urgency last year.

The new law requires some beneficiaries to re-confirm their circumstances at least once every 52 weeks, to check whether they are still eligible.

That saw thousands of pensioners missing out on their Winter Energy Payment this year, which the Prime Minister Christopher Luxon and Social Development Minister Louise Upston apologised for last week.

The Winter Energy Payment should have been excluded from the legislation.

MSD has now confirmed to RNZ there was another separate problem: due to the high volume of people confirming their circumstances, some of them missed out on their benefit payments.

"Some responses were not fully processed before their expiry date, and some payments were suspended despite people providing the information we requested," said service delivery group general manager Shannon Soughtton.

"We apologise to those affected and recognise the impact this may have had."

MSD could not confirm how many people were affected or how long payments were suspended for, because that information was held in individual client files.

All payments had resumed and been backdated, Soughtton said.

"Processing volumes are now back at expected operating levels, and we are keeping pace with incoming demand."

The delays did not affect most beneficiaries because not everyone needs to confirm their circumstances, she said.