No forced Aust Post redundancies

Australia Post won't force staff to take redundancies as part of its planned two-speed mail service.

Australia Post chief executive Ahmed Fahour expects the total number of staff employed at the publicly funded mail-delivery service to increase as part of the changes and has ruled out forced redundancies.

However, he couldn't confirm there would be no job losses in regional Australia.

From September, regular letters will take up to three days to arrive, while next-day delivery will attract a premium price.

The changes are in response to the dwindling demand for letters, with around 97 per cent sent by businesses and government.

Mr Fahour told a Senate estimates hearing on Wednesday there was still a lot of consultation with customers, employees and unions to be completed before the changes are implemented.