Coltman, who turns 23 in January, has played 22 ITM Cup matches for Otago over the past three seasons. He was in the Highlanders' Wider Training Group in 2012 and was also a key member of the New Zealand Under 20 team that won the world title in 2010.
Emery is playing in his first ITM Cup season for Manawatu and has been impressive in the Turbo's mid-field since making his debut earlier this season.
He was part of the New Zealand Under 20 Team that played in World Championship in South Africa earlier this year.