These job losses would be part of the 1500 to 2000 frontline and back-office job losses across the business announced in 2013.
A NZ Post spokeswoman said talks had started with affected staff.
"We know this will be a stressful time for them and we will support them through our Future Zone programme, which has been designed and resourced to help people with career changes."
Mr Smout said delivery targets would still be met for standard letters.
"We're confident customers will see very little, if any, difference in the services they receive from New Zealand Post as a result of these delivery changes. This is a priority for us," Mr Smout said.
"Our target of 95 per cent of standard mail delivered within three working days remains, just as it is now. Six-day-a-week deliveries will continue for priority mail and courier parcels, so people should still check for mail every day."
Alternate delivery days will be tested in parts of Auckland centred around Ellerslie to fine-tune the changes before the July rollout.
Priority mail and rural deliveries would remain largely unchanged, Mr Smout said.
A 'money grab' by Government
The Postal Workers Union advocate Graeme Clarke described the changes as a "money grab" by the Government.
"While the union realises changes are being forced by declining mail volumes, New Zealand Post is restructuring its operations to maximise profit at the expense of service to householders and businesses," Mr Clarke said.
He said a reduction of the mail delivery service by the government was "encouraging privatisation".
A pilot project of electric vehicles to deliver mail would be carried out in New Plymouth, which drew criticism from the EPMU, which said would make former employees become contractors.
Auckland Chamber of Commerce chief executive Michael Barnett said the change wouldn't have a significant affect on businesses.
"I really can't see any downside for businesses for what's going to happen," he said.
Mr Barnett said businesses small and large were conducting most of their communications and billing digitally.
"The practices of business has changed dramatically over the last decade," he said.
He said he thought all business owners would be fluent with simple technology like Microsoft Word and email, but slow adapters may need to look to get up to speed.
"I would have thought most businesses are competent in those areas now and would be using them," Mr Barnett said.
"You can understand why there's been a huge reduction for the need of hard copy communication."
Executive Officer of SeniorNet Grant Sidaway said the decrease in mail deliveries would be "one of many things" that were changing in society and encouraging older people to get up to date with technology.
He said the increase in people wanting to get up to speed with doing things online had been noticeable in recent years.
"In the past four to five years it's been pretty evident that those who hadn't learnt earlier on are really keen to find alternative ways in transacting."
Posties get mobility scooters
NZ Post also revealed it is to extend a trial of customised mobility scooters that allow posties to deliver both parcels and letters.
The two and three-wheeled electric scooters were trialled in Wellington's Hutt Valley last year. NZ Post said today it will hold more extensive trials of combining letter and parcel deliveries, including a pilot in New Plytmouth to test the vehicles further.
- additional reporting BusinessDesk
