A decision on Trans-Tasman Resources' application to extract iron ore from seabed off South Taranaki may be pushed back to June.

The EPA's decision-making committee was supposed to finish on March 20, but it has put out a proposal to continue hearings until May 8, because there were a number of evidential matters still to be addressed. It then has 20 days to make its decision.

An EPA spokeswoman said the changed schedule was just a proposal.

"It will be confirmed when parties have provided feedback and the decision-making committee have had a chance to review the feedback."