Kersten, who was selected with pick No.34 in the 2011 NAB AFL Draft, signed a one-year extension, tying him to the Cats until the end of the 2014 season.
The 20-year-old, who is yet to make his AFL debut, committed to Geelong late in the season before going on to kick 24 goals in his last six VFL games.
Entering his third season, the 190cm goalkicker is expected to push into Geelong's forward line and replace James Podsiadly, who was delisted on Thursday.
Hamling, who was selected with pick No.32 in the 2011 Draft, is also yet to debut but has shown encouraging signs in the VFL both forward and in defence.
The 20-year-old, who missed 11 games in 2013 because of an ankle injury, has also signed a one-year extension for 2014.
As well as Podsiadly, who hopes to play on at another club, Geelong has delisted Josh Hunt, while free agents Paul Chapman, Joel Corey and Corey Enright are yet to re-sign.
Chapman's manager Liam Pickering indicated on Thursday that Chapman was almost certain to play on in 2014, but it was unlikely to be at Geelong.
Twitter: @AFL_Nathan
