It is the 29th year of the event, which will be held in a large marquee at the Cromwell Racecourse.
Cromwell's town centre will share the atmosphere with local and travelling musicians busking in the mall from 10am Friday and Saturday.
Event founder Ferg Mitchell said he hoped for good weather and a huge crowd.
''Every year it's like one big happy family getting together.''
The event is popular with people travelling in motorhomes, he said.
''We know of a lot of people who come from the North Island and stay for the weekend.
''Word of mouth has helped the popularity to increase each year. From the beginning it just grew and grew.''
Mr Mitchell started the event in 1986 at the now-closed Hakataramea Hotel, in the Waitaki Valley.
It was also held in Otematata and Omarama before finally landing in Cromwell in 2013.
About 900 people attended last year's event, 200 of whom came in motorhomes, and organisers were expecting similar numbers this time.
It was now one of the highlights on New Zealand's country music calendar, he said.
The action will begin at 4.30pm Friday, with a blackboard session in which anyone can walk up and play. A similar show will be held the next day at 10am.
At 1pm Saturday invited guests will play before a a country music showcase kicks off at 7pm, headlined by Hamilton-based singer Joy Adams.
The hoedown will end with another blackboard show, beginning at 10am Sunday ending in a large jam session.
Alcohol and food will be available at the event.
Separate tickets, plus a $50 weekend pass, will be sold at the venue.
