Total arrivals from Victoria across New Zealand were up 18 per cent for the same period.
The extended campaign will include billboards, social and digital media advertising showcasing iconic Northland sites like Cape Reinga, Tane Mahuta, Bay of Islands and the Poor Knights.
The campaign will also feature the West Coast, targeting travel between March and May.
Australia is Northland's - as well as New Zealand's - largest international tourism market.
Aussie tourists spent an estimated $74m in Northland last year and $2.8 billion nationwide.
Northland Inc regional promotions and tourism general manager, Paul Davis, said he expected the campaign to have a significant impact in the shoulder season.
"That is the ideal time for Northland to have a higher profile in the Australian market. The other thing this campaign hopes to do is to target repeat visitors returning to visit specific regions rather than the entire country," he said.
Mr Davis said more visitors during the shoulder season of March to May, and even into the winter months, would ensure job security for Northlanders employed by tourism operators.
Apart from the Tourism NZ campaign, the Air New Zealand Summer of Safety video featuring Northland will play again on all appropriate Air New Zealand flights until February 28.
According to Tourism NZ, 36 percent of Australian tourists to New Zealand are from NSW, 26 percent from Queensland, 22 percent from Victoria and 7 percent from Western Australia, while South Australia is just 4 percent.
Estimated annual spending in Northland by overseas and local tourists topped $1 billion last year, for the first time.