"Marshall is trying too hard. He just needs to relax and the big throw will pop out," she said.
Hall, the New Zealand and Oceania champion for the past two years, has the goal this season of throwing 57m to qualify for next year's World Student Games in Erzum, Turkey.
If he does this he will break the Otago record of 56.86m held by Robin Tait (Ariki). It is the oldest senior record in the Athletics Otago record book and was thrown on July 3, 1966. Hall (22) will defend his New Zealand discus title in Dunedin at the end of the month.
He has the best nine throws in the country this season and heads the national ranking list with the 51.96m he threw at the Caledonian Ground on Saturday. No other New Zealand thrower has reached 50m this season.
Hall's throws are: 51.96m (Dunedin, February 26); 51.84m (Dunedin, October 9), 51.78m (Timaru, January 8); 51.53m (Cairns, September 25); 51.38m (Dunedin, December 4) and 50.55m, 50.48m, 50.36m, 50.32m.
Keri Tongalea (Auckland) is second with with 49.28m and Hall's training partner, Keiran Fowler (Taieri), is fifth with 46.55m. Bates is becoming impatient and wants Hall to crack the 52m barrier.
"I'm getting sick of the 51m," she said.
"Marshall has thrown the mid-50s in training. He just has to do it in competition. I know the big throw is there. It's on my bucket list and I want to tick it off."
Hall joined Bates squad from his home town of Invercargill when he became a psychology and commerce student at the University of Otago.
"I want that record and I'm going to get it," Hall said.
"I know that I'm capable of doing it if conditions are right."
Hall had intended to compete at the Melbourne Grand Prix meeting at the weekend but it has been cancelled.
Options now are the Canterbury championships that have been transferred from Christchurch to Timaru because of the earthquake and the weekly meeting in Dunedin. Hall will then take it easy before the New Zealand championships at the Caledonian Ground on March 25-27.
If Hall does not reach his target distance by the end of the national championships he still has another option when he competes in three or four meetings in California in April.
"It will be ideal competition for Marshall because he will be against athletes who will throw between 55m and 60m," Bates said.
"I'm confident he will reach the target."
Hall has concentrated on making small technical changes during the last few months and should have mastered the changes by the time of the national championships.
"He is changing the line of his footwork in the circle and concentrating on keeping his shoulders high during the throw," Bates said.
Marshall Hall
At a glance
Age: 22.
Home town: Invercargill.
Occupation: Psychology and commerce student, University of Otago.
Sport: Athletics.
Coach: Raylene Bates.
Event: Discus.
Best throw: 51.96m.
Record: NZ champion 2009, 2010; Oceania champion 2009, 2010.
