Parts of mining magnate Andrew Forrest's plans to renovate his heritage-listed Cottesloe mansion have been labelled "overpowering" by the town council's deputy mayor.
The billionaire's ambitious proposals to demolish and rebuild sections of Pine Lodge have stalled after the Town of Cottesloe raised concerns and sent the plans back to Mr Forrest's architects.
The single-storey brick house dates back to 1896 and is deemed to have great cultural heritage significance.
Mr Forrest, whose fortune is estimated at $4.4 billion, wants to build a carport with a bedroom above it, a new swimming pool, a plant room, a media room, a cellar and a gym as part of the estimated $2.5 million renovations.
But the council believes that parts of Mr Forrest's submitted designs breach local planning regulations, prompting eputy mayor Jack Walsh and other councillors to vote to defer decision on Monday.
Mr Forrest also wants to build boundary walls as high as 4.5m, which the council says do not comply with the Residential Design Code, while the proposed two- storey carport reaches 7.44m, which the council says is higher than the Town Planning Scheme No. 2 allows.
Mr Forrest bought Pine Lodge in 2000, the same year the Federation Queen Anne-style property was added to the State Register of Heritage Places where it is described as "finely designed" and "displaying quality craftsmanship".
Heritage Council WA said it supported Mr Forrest's plans, the areas earmarked for demolition had little heritage value and the additions were distinguishable as new works. But town planners said the Heritage Council's response fell short of Pine Lodge's heritage value.Cr Walsh said height of the boundary walls was "overpowering" and Mr Forrest's architects were meeting town planners this week to discuss the plans further.