After weeks of sweltering temperatures, punters are being told to pack their gumboots for the Duvauchelle A&P show in Canterbury.

The show's junior vice president, James Dwyer, says the area has had about 80 millimetres of rain since early Wednesday morning.

The three days of rain has already cancelled the Peninsula Duvauchelle Shears competition.

Dwyer said the problem is the sheep need to be off the paddock and fasted for about 12 hours prior to the competition.

"We can't put the sheep into the shearing sheds because with all the wet wool on them and the wet sheep yards the wool will go from a lovely white to a horrible browny green."

He says the timing is disappointing after weeks of sweltering temperatures.

But the rest of the events are going ahead today and despite the bout of bad weather Dwyer said they're still expecting a strong turnout.

"There'll be cruise ships coming into Akaroa Harbour so hopefully we'd like to think some of those visitors will come in experience a little bit of local A&P show."

Dwyer said they've adjusted some horse jumps so the animals land on an incline and have a firmer footing, and tractors are at the ready to haul horse floats and the like from soggy ground should the need arise.

Dwyer said tractors have already had to rescue some vehicles from the wet and they're on standby for when the show finishes.

"Some of them have got some good puddles around the tyres and the proof will be in the pudding I suppose on Sunday morning when they try to leave. So we've got a couple of good sized tractors here with some good strops and chains."