If United win the last two fixtures they are guaranteed promotion. United's goals were scored by strikers Brad Hill and Shadley Petersen, captain Lawrie Scott, Sam Robinson and Harawira Smith.
Meanwhile, Ngongotaha were beaten by Tauranga City 2-0 on Saturday.
Ngongotaha remain in fifth spot on the Federation One ladder. AFC Fury (Tauranga) are closing in on the Federation One title after beating Matamata 2-0 at the weekend.
Results
Waikato Bay of Plenty Football results on Saturday:
Federation One: Melville 1 Otumoetai 1, Matamata 0
AFC Fury 2, Tauranga Boys' College 0 Cambridge 3,
Hukanui Rototuna 1 Tauranga Old Blues 3, Ngongotaha
0 Tauranga City United 2, Waikato Unicol 1 Taupo 1.
Federation Two: Tauranga City 5 Cambridge 0,
Papamoa 3 West Hamilton 0, Rotorua United 5 Katikati
2, Te Awamutu 2 Ngongotaha 2.