Next weekend is ummm New Years so a 4 day weekend is wasted surfcasting.
Weekend of the 15/16th is probably Kaikoura Surf contest (maybe Amberly also?). While I am not planning on fishing them, many here probably would. If its going ahead, the Nape Nape contest is normally the weekend after (22/23).
So that only leaves the weekends of 8/9th or 29th/30th for January.