Second-seeded Barnett got off to a quick start winning the first game 11-4 and was 6-1 up in the second before Epke slowly started to assert her dominance, battling back to win 4-11, 12-10, 11-9, 11-5.
It is the first time Williams and Eke have been crowned champion at the North Island Open Championships.
Results.
Men: Quarter-finals
1. Evan Williams (Wellington) def Joelle King (Waikato) 11-5, 11-2, 11-6
4. Chris van der Salm (Canterbury) def Jonny Barnett (Canterbury) 11-9, 11-6, 8-11, 11-4
3. Ben Grindrod (Bay of Plenty) def Sam Atkins (Wellington) 11-6, 11-8, 12-10
2. Lance Beddoes (Auckland) def Luke Jones (Central) 11-6, 11-5, 12-10
Semifinals
1. Evan Williams (Wellington) def 4. Chris van der Salm (Canterbury) 11-4, 11-8, 10-12, 11-3
2. Lance Beddoes (Auckland) def 3. Ben Grindrod (Bay of Plenty) 11-8, 5-11, 11-5, 7-11, 11-9
Final
1. Evan Williams (Wellington) def 2. Lance Beddoes (Auckland) 11-9, 11-3, 9-11, 11-9
Women: Quarter-finals
1. Ellie Epke (Auckland) def Priscilla Wildsmith (Auckland) 11-9, 11-6, 13-11
4. Abbie Palmer (Auckland) def Hayley Hughes (Auckland) 12-10, 11-7, 11-4
3. Danielle Fourie (Central) def Nadine Cull (Waikato) 11-2, 11-1, 11-4
2. Rebecca Barnett (Central) def Juee Bhide (Auckland) 11-7, 12-10, 11-7
Semifinals
1. Ellie Epke (Auckland) def 4. Abbie Palmer (Auckland) 11-5, 11-4, 10-12, 11-6
2. Rebecca Barnett (Central) def 3. Danielle Fourie (Central) 4-11, 11-2, 5-11, 11-8, 12-10
Final
1. Ellie Epke (Auckland) def 2. Rebecca Barnett (Central) 4-11, 12-10, 11-9, 11-5