The 2003 New Zealand National Club Championship, also known, due to naming-rights sponsorship, as the Southern Trust National League was the fourth and final season of a nationwide club competition in New Zealand football. The competition was won by Miramar Rangers.
The league was played mainly during autumn, with matches played from February to June, and was run in two stages. In the first stage, each team in the ten-team league played every other team home and away. In the second stage, the top four teams entered a knockout competition, with third place playing fourth place in one match and first playing second in the other, with home advantage being decided by final league position. The winners of the first against second match progressed straight through to the final; the losers of that match met the winners of the other match to decide the other finalist.
This was the last season of the league, which was replaced by the New Zealand Football Championship. It had become clear that teams were having to amalgamate to create financially viable strong teams to take part in the league, most notably the Canterbury and Auckland-area conglomerate teams Canterbury United and East Auckland. It was decided by the NZFA that an eight-team franchise-based national competition would be more viable and successful than a club based competition. Club-based teams returned to regional leagues, and became feeder clubs for the regional franchises. The new competition debuted in October 2004.
Rules for classification: 1) points; 2) goal difference; 3) number of goals scored. (C) = Champion; (R) = Relegated; (P) = Promoted; (E) = Eliminated; (O) = Play-off winner; (A) = Advances to a further round.
Only applicable when the season is not finished: (Q) = Qualified to the phase of tournament indicated; (TQ) = Qualified to tournament, but not yet to the particular phase indicated; (RQ) = Qualified to the relegation tournament indicated; (DQ) = Disqualified from tournament.