The submission period on whether a section of seabed off the west coast of the North Island, has been extended a month because the Environmental Protection Authority did not give enough time for the public to view all relevant documents.
Trans-Tasman resources wants to mine iron ore from 65 square km of seabed, 22km off the coast of Patea.
Submissions on whether a marine consent should be granted were supposed to end on Friday.
However, the EPA admits documents were not available on its website for submitters for all of the submission timeframe.
Radio New Zealand understands this includes an overview report of the project and maps.
Submissions now close on 28 January.