Turner said: "Aled is a talented player but he needs to develop some consistency in his game. He scores tries for fun and kicks the ball well but if he can keep improving, he'll become a Wales regular rather than just winning the odd-cap.
"He's someone with the X-Factor but I'm constantly on his back to get the best out of him."
Brew, 23, enjoyed his best form during a season-long loan at the Dragons in 2006-7, that earned a Wales debut in that year's Six Nations.
Following wayward spells across the regions, the Wales Sevens World Cup winner returned to Rodney Parade last season.
Now Brew is back to his best and currently joint top-scorer in the Magners League with four tries this term.
Brew said: "I've really enjoyed my time at the region and I feel this team are going somewhere. I've developed well as a player here and the team has a bright future."
The Dragons have also snapped up Wayne Evans, Martyn Thomas and Tom Riley on new deals until 2012 while the Gwent region have agreed a two-year extension with shirt sponsors Motorpoint.