McCall is the New Zealand matchplay and strokeplay champion and is one of a handful to achieve this feat in the same calendar year.
He was also the top Kiwi performer in the recent Eisenhower Trophy in Turkey.
The Tapanui-based golfer won this event four years ago and has opted to play in the 100th championship rather than compete in the Charles Tour event at Shirley in Christchurch.
However, McCall will not have everything his own way as there are four other former champions in this weekend's field.
They are Liam Balneaves (2005 and 2010), Tony Giles (1993 and 1996), Brent McEwan (1998 and 2011) and Michael (Moxy) Smith (2007).
The event will also double as a crucial trial for players who were in the triangular 10-man team as that number will be reduced to eight on Monday evening at the conclusion of the championship.
The inaugural event was played at Balmacewen in 1903 but there were no events held during the two world wars, leaving this weekend's event as number 100.
Ken Ross heads the list of winners with seven titles, followed by Ron Timms who won five championships before turning professional in 1966.
C.B. (Chris) Wight was a prolific championship winner with 19 St Clair Club senior championships, and, like B.V. (Pip) Wright, won four Otago titles.
Along with Alec Sime (1922), Tony Gibbs (1948), current selection convener Ben Gallie (2001) and McCall (2012), Wright also won the New Zealand amateur championship in 1933.
Traditionally the championship was decided over four days at Easter with a 36-hole final on Easter Monday.
However, the fields were dwindling with families preferring to take holidays.
With only 23 entries in 1982, the event was postponed. It was eventually won by Greg Turner after a seeded matchplay draw on Sundays in July.
Since then the event has been held during Labour Weekend which is ideal as the Toro interprovincial teams' event is now played in November or December.
With the interprovincial at Balmacewen on 4 to 8 December this year, there will be keen interest in how the triallists perform on the hilly terrain.
