She gave the young musicians pointers on how to perform well as an ensemble and the session gave them a chance to polish the finer details of their performance.
Music teacher Kathyrn Lauder said the opportunity to have someone of Douglas' calibre was priceless and gave the students a "boost of confidence".
"It was a fantastic experience . . . As well as coaching the group, she also shared about her own experience of learning music," she said.
Lauder said it was rare to work with someone of this experience and expertise and an hour session made a real difference.
Chamber Music NZ artistic administrator Elizabeth Bisley said the upcoming National Chamber Music Competition was the perfect opportunity for young musicians to compose and to perform chamber music and strive towards excellence.
She said the contest, which celebrated its 50th anniversary in 2015, was "iconic" and inspiring and had launched the careers of many young musicians and composers.