All the open competitions are January/Febuary with sometimes the Birdlings Flat one in March. The main ones worth entering are probably Kaikoura, Nape Nape and Birdlings Flat. Last year there was also a competition at South Rangitata at the start of January, not sure if it’s a yearly thing or not.
But yeah, all the information will be on the forum closer to the dates.
Also will be a fair way to travel from South Canturbury