Also among 59 submissions on the tram environmental impact statement, the racecourse raised concerns about horses being spooked during construction of the tram line and requested sound barriers and noise restrictions during races and during training, 4.30am to 9.30am.

The start position for some races was just 50 metres from a works depot, Canberra Racing Club head Peter Stubbs said. "Sudden and loud noises and movement have the potential to frighten horses, with the potential consequence being injury to riders and horses."

Canberra CBD said it had met with senior bureaucrat Dan Stewart and Capital Metro head Emma Thomas and they were "maybe open to seeking an alternate location for the construction compound or installing a temporary multistorey carpark adjacent to a smaller construction compound".

The meeting had also discussed using Haig Park as a works depot, or using the Northbourne public housing precinct and other land on Northbourne.

The group urged the government to pursue the alternatives, including bringing forward the development of the City West carpark on London Circuit. And it urged the government to site the tram terminus between the Sydney and Melbourne buildings, rather than at Alinga Street, which it said was too far north.

The Interchange General Practice was among a number of health practices opposing the carpark closure. Principal Dr Tuck Meng Soo said the practice had around 25 doctors, with 30,000 patients a year, many of whom had limited mobility and couldn't catch a bus. The carpark had 10 doctor's parking spaces, for which doctors paid $1000 a year.

The Charcoal restaurant said the closure would threaten the future of the business, and to expect elderly and handicapped people to walk from the Canberra centre or Marcus Clarke Street was "unrealistic and farcical".

A patient of Canberra City Osteopathy said she had to drive to the clinic: "Canberra is not Manhattan, Paris or London. It will not make Civic more vibrant if people cannot get there to use businesses." She said she would love to use public transport, "but the completely inadequate street lighting where I live means that I can never return home after dark by any method other than driving. I do not want to stumble alone through completely dark streets".

Melbourne Building businessman David Harrington said he supported the tram, but the closure of the carpark for up to four years was unacceptable, ill-conceived and likely to have "a direct and dire effect on many businesses in the area".

A Richardson resident put the carpark issue bluntly: "Instead of closing the car park adjacent to the Melbourne Building for four years, wouldn't it be better to set up the construction compound on part of the demolished Northbourne Ave flats? Seriously this whole concept and application are a crock."

The National Archives raised concerns about the effect of vibration during earth compacting at a bridge being built for the tram, and said the building had not been identified as dust sensitive, despite air intakes on its southern side. "How will the potential risk of the dust on the base building plant and equipment be mitigated?" it asked, pointing also to the possibility of problems at its new building in Vicars Street, Mitchell.

Owners of the Northbourne and Miranda lodges on Northbourne Avenue are worried about access, overnight noise for guests and disruption to their businesses.

Others questioned the choice of Brittle Gum as the new trees for Northbourne. "Can you assure us that they will be safe? I feel unsafe standing under them, especially in windy weather," one submitter wrote.