Between 1,100 and 2,450 hectares of Marlborough vineyard area were unlikely to be pruned before budburst this year, according to new modelling.
The rest of the country will remain at Alert Level 2.
Ardern’s announcement follows a Cabinet meeting today and the advice of Director-General of Health Dr Ashley Bloomfield.
The lockdown was originally aimed at ending at midnight on Wednesday.
Ardern says the Government wants confidence and certainty before moving Auckland down to Alert Level 2. She says this will require falling numbers and clear evidence the cluster is being circled.
Ardern says with Bloomfield's guidance, such confidence and certainty could be achieved this week.
She says restrictions on mass gatherings will remain in Auckland on Monday, even if it moves down to Level 2.
The rest of the country will remain at Level 2 for another week.
She says these two settings will be reviewed by Sunday 6 September, one week from the extension ending.
Masks will also be required at Level 2 and above levels on public transport from Monday.