"There is now an opportunity for alternative applications to be considered alongside those from the councils," he said.
Mr Riezebos said an alternative application is not the same as a submission that merely expresses a view or takes a position on the councils' applications.
"Public submissions occur at a later stage of the process," he said.
An alternative application is expected to propose changes, to explain what they are designed to achieve and to describe improvements that would result from the changes.
"For example, changes can include the union of district or regional councils, the creation of a new district or regional council, the abolition of a district or regional council, boundary alterations or the transfer of statutory obligations between councils," Mr Riezebos said.
The commission will receive alternative applications until August 16 and consider them alongside original applications as well as the status quo.
Further along the track the commission will determine its preferred option and will prepare a draft proposal which will be publicly notified and public submissions called for.
If it decides to press ahead, the commission will prepare a final proposal which will also be publicly notified.
Then 60 working days are allowed for responses which could include people seeking petitioning for a poll.
A petition of 10 per cent, or more, of electors in any affected district is able to trigger a poll.