He said the owners, Shell and Todd Energy, had already submitted an application for a permit but if there were any appeals that were not resolved before June the platform would be operating illegally.
Dr Smith said if the Maui A platform was unable to operate, it would reduce New Zealand's supply of gas by 40 per cent. A "narrow" amendment would allow the platform to continue operating until the appeals were finalised.
The problem arose because the Maui platform had a mining permit before the EEZ bill was passed, and it was now required to get consent to operate in the EEZ before its permit expired. The expiry date for its current permit is June 28.
The minister said the law change related specifically to the Maui A situation, and would not affect other mining consents.
The Green Party was concerned that any amendments to the EEZ would be in response to recent decisions to reject mining permits in Taranaki and Chatham Rise.
Green Party oceans spokesman Gareth Hughes said the minister could not rule out making it easier for seabed mining companies to apply.
"The worst outcome could be if they make it easier for their corporate mates," he said.
Officials have recommended to the minister that changes were made to clarify the laws in the marine space where environmental and economic interests were competing.
Dr Smith said there would be no surprises in the amendments.
"It isn't a radical shift in the legislation," he said.
