"I think last year they had about 8000 here for the event but indications are this year's meeting will be much much bigger."
He said they could assume at least 4000 of those visitors last Boxing Day were day trippers and, using the multiplier factor, that meant a return to the local economy of $416,000 in day trippers alone.
He said his team used the multiplier factor to work out expected dollar value of boosted visitor numbers and it copied a system devised by Tourism NZ.
"We work it out based on a day visitor spending $104 here while someone overnighting will spend $350," he said.
"But the difficulty is getting the exact detail of numbers here. That's something we usually can't get until after the event."
He said from this weekend through into the New Year a series of major events was lined up which promised to boost local business coffers.
"We've got the Billy Webb event this weekend, which is coupling up with the Jury Cup regatta.
"Then there's also the hydroplanes here for the Acceleration On Water - Festival of Speed on the Whanganui River," Mr MacGibbon said.
"It's hard to estimate numbers here for the Billy Webb because there's no entry fee.
"However, we can assume there will a good number here for that and a good number we can expect will overnight."
Mr MacGibbon said the Billy Webb regatta had, until this year, been more of a local event in terms of its stature but this year he had noticed a marked shift.
"It's been getting some amazing national coverage and it's been talked up on radio, especially for at least the last two months. Some of that will be riding on the success of the Olympic rowers."
As well as the motorcycle meeting, there was the national jetsprints on the day after (December 27).
Into the New Year, there's the week-long Festival of Cricket which attracts hundreds of juniors, parents and families.
Capping it off are the NZ Masters Games, from February 1-10.