The Ministry of Fisheries has approved 10 new marine farms, increasing the area allocated to aquaculture by 3143 hectares.
A proposed new off-shore mussel farm at Pegasus Bay in Canterbury, which will be New Zealand's second largest marine farm, will take up most of that space.
A 424 hectare marine farm in Clifford Bay on Marlborough's east coast and eight small operations in the Marlborough Sounds have also been approved.
The ministry's aquaculture manager, Dan Lees, says none of the farms will affect the sustainability of the fishing resource.
He says the one off Pegasus Bay will be split into four areas of 515 hectares each.
Mr Lees says the ministry paid particular attention to protecting the Hector's dolphin before approving the Clifford Bay marine farm.
"A lot of concerns were raised because this area was thought to be important for Hector's dolphins.
"Three years of monitoring has now been conducted and it's looking like the site isn't of any particular significance for the dolphins."
Mr Lees says he expects work on the eight small farms in Marlborough Sounds to start early next year.
Minister wants more aquaculture space
Fisheries Minister Phil Heatley has welcomed the approvals.
But he says they were applied for years ago under the old aquaculture laws and no new marine farming space has been approved under the 2004 reforms.
Mr Heatley says aquaculture has huge potential for generating economic growth for New Zealand, but more space must be allocated if the industry is to meet its target of being worth $1 billion a year by 2025.
He says a technical advisory group is working to address the issue.