Steamers coach Kevin Schuler says Hagen is a useful addition to the squad.
"Elliott came over and played for us in the pre-season but when we took Dave Thomas he went home but has now come back here to live and played development last week," Schuler said.
"He is an attacking-minded and energetic young player, who has a good kicking game and good eye for the gap."
There is no doubt Wellington will be hard to topple, especially at home, but the Steamers are more than capable of knocking anyone over if they produce their A game.
Schuler says there are some obvious areas they must tighten up that let them down against Canterbury.
"Our one-on-one tackles weren't good enough so we missed a lot and that led to their tries. Also some systems stuff and make our forwards go to work in close. But we have an attacking mindset so we are still creating opportunities and we need to make sure we finish them.
"We have to put in some big tackles and knock them over, as they are a team that like running, and their first instinct is to attack. They challenge any team in that regard so we need to rise to the occasion and be confident we can get up and knock them over. If we do that it takes away their offload game so that is a real key focus for us."