Work began this week on stage four of the TSB Hub in Hawera.
The multimillion-dollar sports and events complex formally opened in March and is undergoing further renovations.
Operations manager Phil Waite said the old grandstand was being dismantled.
The number one rugby ground would be re-aligned to face the new grandstand.
The numbertwo rugby ground would also be aligned, and a number three ground made for rugby league.
"We're going to have lighting installed here - four big lights for the number one ground, and smaller lights for the other grounds," Mr Waite said.
"So the level of lighting will be considerably higher than it is now."
Drainage will be laid under the grounds.
The grandstand demolition work was hampered by heavy rain earlier in the week.
That had caused minor flooding on the grounds and made operating heavy earth-moving machinery impossible.
Mr Waite said once the drainage system was in place, flooding problems should be a thing of the past.
Stage four was expected to be finished by the end of the year.
The price tag for stage four is $6.25million.
Funding has come from TSB Community Trust ($3million), the Ministry of Education ($1.5million), New Zealand Lottery Grants Board ($500,000), New Zealand Community Trust ($400,000), Pelorus Trust ($100,000), Southern Trust ($100,000) other trusts, businesses and community fundraising ($1.05million).
The total cost of the TSB Hub project is $21,098,210, with $14.89million coming from the South Taranaki District Council by way of a loan to be repaid by interest earned from a long-term investment fund.
