The Government-owned company's result was up from $94 million reported in the previous corresponding period.
After-tax profit was up 40% from $71 million to $100 million, while revenue was up from $860 million to $879 million.
NZ Post will pay an interim dividend to the Government of $2.5 million.
Chief executive Brian Roche said the overall result confirmed the group was ''moving in the right direction'', although it was still a challenge to get a return on investment in its core business, which was mail and logistics.
Letter volumes were down 36 million items, or 9.8%, compared with the December 2013 half-year.
NZ Post is moving to a three-day a week mail delivery in urban areas from July 1.
A growth in parcels, driven primarily by substantial growth in e-commerce activity and an associated growth in inbound parcels from overseas before Christmas, helped offset the continuing decline of the traditional letters business, Mr Roche said.
Kiwibank this year expected to pay its first annual dividend after 13 years of operation, reflecting its increased size, record profits and its ability to fund its own activities.
Kiwibank's operating profit was $88 million, up 46.3% from last year's $72 million result, while after-tax profit was up from $52 million to $71 million.
At a briefing in Wellington, chief executive Paul Brock declined to forecast the level of the dividend, saying it was dependent on the annual result, but said the bank expected to now continue paying dividends in future years.
''We are in a self-funding position right now, so we have no more intentions to look for additional capital from the shareholder at this stage,'' Mr Brock said.
Total lending (home loans, business banking and credit cards) increased 2.9% from $14.63 billion to $15.05 billion.
Customer deposits increased 4.2% from $12.75 billion to $13.28 billion, while operating revenue was up 14.1% from $231 million to $283 million.
The result continued the strong recovery after the financial constraints resulting from the Canterbury earthquakes and the global financial crisis, Mr Brock said.
The underlying strength of the performance was improved net interest margin and containment of costs.
Margin improvement was driven by favourable funding conditions, as lower funding costs provided an offset to lower lending margins resulting from strong competition and customer preference for fixed-term loans.
Kiwibank had 880,000 customers at the end of December, which was ''basically one in four of all bank account holders in New Zealand''.
Of that, 418,000 were considered main bank customers, representing an 11.6% market share, he said.
- Additional reporting BusinessDesk
