The reserves would ban all fishing, mining and petroleum exploration within the protected areas.
Dr Smith has made marine protection one of his top priorities because 70 per cent of New Zealand's native species were found in the ocean.
The National-led Government is aiming to establish a record number of reserves this year.
The addition of the new reserves would mean that 9.56 per cent of New Zealand's territorial waters - the area out to 12 miles from the coast - was protected.
Conservation groups welcomed the establishment of new reserves and encouraged Government to continue increasing the proportion of protected areas to unprotected areas.
If the entire Exclusive Economic Zone was taken into account, around 0.4 per cent of New Zealand waters was a no-take zone.
In comparison, a third of New Zealand's land was protected.
The five island groups which make up the Subantarctics are one of just three sites in New Zealand which have been granted World Heritage status.
WWF NZ head of campaigns Peter Hardstaff said his group was delighted the Government had set up marine reserves around the islands, "because this kind of protection is vital if we are to be effective stewards of our oceans and the animals that live there".
"However, while new reserves are welcome, what New Zealand needs most of all is a comprehensive plan for looking after our marine environment," he said.
"We all need to be clear on where we want protection, where we can fish and what other type of activities will be allowed. Let's do it once and lets do it right. Our oceans deserve it."
Mr Hardstaff said legislation to set up a comprehensive marine spatial plan for looking after our oceans should be a priority for the Government and whoever was in power for the next term.
"This plan needs to include setting aside our most ecologically important marine habitats and a good starting point would be to create a Kermadec Ocean Sanctuary.
Biggest marine reserves
* Kermadec Islands Marine Reserve (1990), 748,000 hectares
* Auckland Islands Marine Reserve (2003), 498,000 hectares
* Subantarctic Islands (2014), 435,163 hectares