West Auckland and the North Shore also had large increases, of 28 and 27.2 per cent respectively.
The only region that had a decrease was Franklin and rural Manukau, which went from $496,593 last year to $483,617, a drop of 2.6 per cent.
In total, the company sold 816 homes in Auckland last month, compared with 676 the same month last year, an increase of 20.7 per cent.
Barfoot & Thompson's managing director Peter Thompson said the company listed 1440 properties last month, the highest number since the boom of 2007. It was 39.7 per cent higher than in the same month last year.
"January is always one of our lowest months for new listings, but interest in selling rolled over into January as a result of the excellent prices being achieved pre-Christmas, and our agents have been active since the first business day of the year.
"The Auckland housing market is showing all the signs that it has picked up from where it left off in December, and that sales numbers and values will hold up through the remainder of the warm months to come."
Real Estate Institute of New Zealand chief executive Helen O'Sullivan said house prices in Auckland were likely to keep rising as the city continued to grow and face supply issues.
"If you want a standalone house in the central suburbs, you're starting to look in that million-dollar figure. And not for a palatial mansion."
New Zealanders weren't yet "emotionally adjusted" to apartment living but that was starting to change.
A new complex in Grey Lynn, The Isaac, had attracted retired buyers, when developers were expecting buyers in their 30s.
Figures from all Auckland house sales for January, compiled by the Reinz, are expected next week.