McDonald has competed in 10 interprovincial matchplay tournaments, including Otago's wins in Taupo in 1978 and at Balmacewen in 1982.
NZG has proposed to change the Toro-sponsored men's and women's interprovincial tournaments, reducing them to four players, in a strokeplay format.
The current format includes five players, competing in matchplay.
McDonald queried the reasons for the change and whether NZG was narrowing its focus too much.
''The proposed format smacks of elitism and is yet another event targeted to the top-echelon Srixon squads,'' McDonald said.
''There is already the SBS interprovincial and North and South Island championships played as strokeplay events.
''In addition to these, there is a plethora of Charles Tour strokeplay tournaments which cater for the leading professional and amateur golfers.
''I was under the impression that New Zealand Golf administers the sport for all players. The retention of the existing format allows for the participation of New Zealand's top 150 leading men and women and not just the elite.
''At present, under the current format, there exists the opportunity in every round for a David v Goliath syndrome.
''However, by their own admission in the format change discussion paper, the change would be detrimental for the weaker provinces.''
McDonald questioned what incentive there would be for weaker districts to put teams into a strokeplay event.
''For many golfers, the current format is the pinnacle of their golfing career. The excitement at the Toro men's and women's events in Dunedin last year epitomises why the existing format is by far the best option.''
Bay of Plenty won the men's event on the second extra hole after it was tied with Manawatu-Wanganui. Auckland won the women's event in a nail-biter, the contest going to the final putt on the final hole.
In contrast, the South Island men's and women's strokeplay events were all over by lunchtime on Sunday. Peter Lee (Rotorua) held a seven-shot lead, as did Munchin Keh (Auckland), with one round to play.
The same scenario was repeated at the SBS interprovincial strokeplay in March. Auckland was too far in front to be reined in during the final round, while Otago No 1 Brent McEwan held an unassailable lead after three individual rounds.
McDonald said the current system worked well. He was also critical of reducing teams to four players and discounting the worst score in each round.
''Currently, all five team members contribute to the outcome, which is as it should be.''
