"We have made a number of errors in the client's case," MSD South Auckland regional director Peter Anderson told the Herald.
"We apologise unreservedly for that. It isn't an acceptable level of service and we know the suspension of her benefit was very distressing.
We suspended the client's benefit because of an allegation we received that she was in a long term relationship not because she went on two dates – we would never stop paying someone for that reason.
"We did need to investigate the allegation we received, but we should not have suspended her benefit so quickly, or without discussion with her. We apologise for this. We have dropped the investigation as we have not been able to substantiate the allegation."
The ministry also said she had failed to attend two Work and Income appointments on April 9 and 10, RNZ reported.
But the woman told RNZ that Work and Income had never raised those allegations with her and nobody had told her about the appointments.
She had been on a benefit since January after her boss tried to make her move to night shifts, which she could not do as the solo mother of three children.