Three Dunedin teams will go into Tuesday's national open draw for the last 16 of football's Chatham Cup after winning their third round regional ties this weekend. 

On a good weekend for football's southernmost region, University were the only Dunedin team to lose their fixture, and then only to neighbours Roslyn Wakari 5-1 as two other Otago teams prevailed against Christchurch rivals.

In one of the tightest games of the round, Dunedin Technical edged six-time winners Christchurch United with a 109th minute Richard Smith strike sealing the 1-0 extra time away win.

Caversham made light work of Christchurch's Western winning 5-2 at Dunedin's Caledonian ground.

The weekend was also good for some smaller centres as Wairarapa United reached the fourth round with a 6-0 win over Red Sox Manawatu fired by a four-goal haul to Adam Cowen.

Palmerston North will be represented in Tuesday's draw by Palmerston North Marist, who upset Petone 2-0 thanks to a brace from Thomas Mosquera.

A first half goal from Stu Wilson earned four time winners Napier City Rovers a 1-0 home win over Stop Out, leaving Wellington United -- 5-2 winners over Upper Hutt City -- as the only team from the capital in the last 16.

The Cinderella run of Westlake Boys High School ended in an enthralling 3-4 loss at the hands of Waitemata, themselves a relative minnow. The students conceded in the first minute but fought back to lead 3-1 only to succumb to three goals in the final 20 minutes with Andrew Williams netting the winner six minutes from time.

Hamilton's two Northern Premier League sides both fell to first division opponents -- Wanderers falling 1-2 to Manurewa at home and Melville pipped 2-3 Birkenhead in Auckland.

Bay Olympic and Central United each posted lopsided wins, Nathan Strom netting a hat trick in Bay Olympic's 8-0 win over Hibiscus Coast, and Luis Corrales and David Mulligan doing the same in Central's 9-1 cakewalk over Forrest Hill Milford.

Meanwhile, Onehunga Sports and East Coast Bays were only four minutes away from a penalty shootout when Haider Jabir netted to give Onehunga a dramatic 2-1 win at Bay City Park.

Three Kings defeated Glenfield 2-0, Waitakere beat Takapuna 3-1 and Christchurch's Coastal Spirit ended Richmond's run with a 5-3 victory in Nelson.