New legislation will impose stricter environmental regulations on New Zealand's large Exclusive Economic Zone.
The country has jurisdiction over an area of sea and seabed between 12 and 200 nautical miles offshore.
Environment Minister Nick Smith says the legislation tabled in Parliament on Wednesday will cover seabed mining and some aspects of petroleum exploration and extraction.
"We do need to put some robust environmental protection laws out into that space, which effectively at the moment has got no regulation."
The legislation includes financial penalties for carrying out prohibited activities, such as constructing or removing underwater pipes or cabling, or causing enough damage to the seabed that marine life would be affected.
The maximum penalty for an individual is $300,000 and $600,000 for a company. There is also a maximum $10,000 a day penalty for ongoing breaches.
The new regulation regime will come under the authority of the Environmental Protection Authority.
Dr Smith says the Government's intention is for the law to come into effect on 1 July next year.