Dunedin City Council parks and recreation group manager Robert West said the top 50mm of thatch material was being removed and the playing fields were being re-levelled by laser.
The No 1 rugby and football fields would then be resown with grass.
Mr West said both fields were uneven, compacted and struggled to get good grass coverage, resulting in a poor playing surface. Hancock Park would benefit by having good quality, well-drained fields.
Work started this week, and the fields were expected to be ready at the end of April.
The work would cost between $50,000 and $60,000.