The rally started out as a birthday party at the Waihao Forks Hotel with a few mates and has grown to become the biggest in the South Island.
Next year, it celebrates its 25th anniversary with a special rally that is being kept under wraps by March Hare Motorcycle Club president Craig Rowley.
Last year, about 3000 motorcyclists set a record attendance.
This year, Mr Rowley is expecting even more if the weather holds.
"Our pre-bookings were up 10% on last year, so this year could be bigger," he said as the first riders started to arrive yesterday morning.
The event gives a big economic boost to Waimate and its surrounding district.
Most stay at the rally's venue, the Waimate Showgrounds, but hotels, motels and camping grounds are booked out as well.
Mr Rowley estimates tens of thousands of dollars is poured into the community during the weekend.
Apart from that spent in the town - many businesses gear up especially, including one hotel which does more than 100 breakfasts - clubs also use it for fund-raising.
The rally's entertainment starts with a band tonight, then tomorrow afternoon includes games.
The "toss the March hare" has been dropped as "it's not PC these days" - but there is a gumboot throwing contest based on accuracy rather than strength.
Other competitions involve the motorcycles, from the best bikes in 10 different classes through to motorcycle musical chairs and prick the balloon, with the pillion passenger holding a toothpick between his or her teeth.
The rally is open to the public today.
The motorcyclists start to leave from 6pm tomorrow.
