It means on an average day The Star is read by 55 per cent more people aged 15-plus than The Press.
Star Media regional manager Steve McCaughan said the growth was fantastic news.
"It reflects all the hard work and effort put in by our team over the last 12 months.
"In a media environment where audiences are fragmenting, it's tremendous to see readership grow for The Star.
"Our combination of unique local news, mass circulation and trust in our newspaper is a winning combination."
McCaughan said the increase in readership and the widening gap between The Star and The Press was a "winning choice" for advertisers.
"We are now putting advertisers’ messages to more people who clearly see The Star as their media of choice.
"I want to acknowledge and thank all our advertisers for their investment with us.
"Without their support it wouldn’t be possible for us to publish The Star free to the people of Christchurch."
