Hunter River Agricultural and Horticultural Association treasurer David Perrott announced the donation at a Maitland Business Chamber breakfast at the showground this morning.

Mr Perrott said the money would be used to restore seating in the 4200-seat CB Marheine grandstand so spectators could use it again.

He said the benefactor asked to remain anonymous

"The offer was made a couple of months ago when he heard we were looking to refurbish the grandstand," Mr Perrott said.

"They were looking to make a contribution to the showground - they recognised it as an important part of Maitland's history."

Mr Perrott said the grandstand had historical significance and had practical uses in modern times.

"Maitland Showground has got a long history and has been a really important part of the history of growth in Maitland," he said.

"Agriculture was so important not only to this area but the state as a whole and the ability for people to show their wares from primary production was very important."

The donation was made on the proviso that the remaining $570,000, plus GST, could be raised to complete the refurbishment.

The society will use its Sponsor A Plank program, which was also launched at Thursday's meeting, to raise the remaining money needed to complete the work.

People can play an active role in the grandstand refurbishment by sponsoring a plank for $100, a joist for $250, a beam for $1000, a post for $2500 or a foundation for $5000.

Sponsors will have their names permanently listed on the grandstand structure.

Mr Perrott said having different levels of investment meant anyone could get involved.

"We're enormously pleased with the generosity of Maitland Business Chamber to enable us to hold this launch in conjunction with the business meeting and we're really conscious of the support we are getting from the Maitland Mercury," he said.

For more information on sponsoring a new piece of the grandstand, contact 4933 5052,

email admin@maitlandshowground.com.au or visit www.maitlandshowground.com.au.