"Kayla is a world class player with her athleticism, speed and ability to read the game," she said.
"She's still a young player but brings plenty of knowledge into the squad as does the likes of Paula and Ellen who have played at the highest level.
"Having that leadership quality is a huge asset for the Stars as we are still a very new club in the ANZ Premiership - those leadership skills are important as we look to build a culture and grow our performances."
Griffin joined the Northern Stars as a training partner during the ANZ Premiership this year having come back from knee surgery, and also made an appearance for the Northern Comets in the Beko Netball League.
The shooter has played in two World Cups for the Silver Ferns and is a former captain of the New Zealand under-21 team. She suited up for a number of teams in the former transtasman competition including the Central Pulse, Southern Steel and Waikato-BOP Magic.
Cullen is a dynamic and athletic defender who holds plenty of strings to her bow including her versatility on defence. Whilst Cullen has a strong preference for the wing defence bib she is equally as adept at goal defence.
She burst onto the netball scene in 2011 when she was named the transtasman player of the League and also made her Silver Ferns debut that year at just 19-years-old.
Halpenny was a foundation player for the Canterbury Tactix before moving to the Waikato Bay of Plenty Magic. She spent time in the NZ U21 and Silver Ferns Development Squads before breaking through to make the Silver Ferns for the 2014 Commonwealth Games in Glasgow.
A handy attacking player who can interchange between goal attack and goal shooter with ease, Halpenny brings a wealth of knowledge and experience to an exciting shooting circle.
Coughlan was a member of the Canterbury Tactix team in 2016 and a training partner in 2017, making a temporary replacement appearance during the season for the injured Jess Moulds. She was also a stronghold in the Mainland Beko team for the past two years.
Cullen, Griffin, Halpenny and Coughlan join Silver Ferns Grace Rasmussen and Maia Wilson along with Holly Fowler and Fa'amu Ioane as the latest signings for the club with just two places remaining.
The ANZ Premiership set to begin again in May, 2018.