The work is planned to start later this year and will be carried out in four sequential stages with corresponding road closures over a 12 month period. Each stage is expected to take up to 16 weeks. This is subject to site and weather conditions.

Stage 1 involves the construction of the roundabout and Gingers Lane up to Stringybark Place.

Stage 2 is Gingers Lane from Stringybark Place to Woodlands Drive.

Stage 3 is Gingers Lane from Woodlands Drive to Grey Gum Drive.

Stage 4 is Gingers Lane from Grey Gum Drive to Frame Drive.

The temporary roundabout will be formalised on Hart and Government roads.

The initial estimate for the project was $2.8 million, which has now been reduced to $1.5million. Council has received an "in-principle commitment" from RMS to fund the roundabout.

Councillor Ian Olsen and residents raised concerns that the reduced estimate meant the quality of the project could be reduced.

"What corners are we cutting to make that roundabout as safe as possibly built," Cr Olsen said.

But council says the cost estimate has been refined as the design has progressed and become more detailed.

"Costs have been reduced as the design assumptions have been tested and refined," a council spokesperson said.

Residents were also worried about the impact of the diversions around works on the roundabout.

The existing slip lane from Hart Road to Government Road will be used in two directions along with a side track connecting Sawyers Gully Road to divert traffic, where residents say there will be a stop sign installed for vehicles entering Hart Road.

The residents fear the stop sign will put added pressure onto the busy intersection as more drivers will be coming from Sawyers Gully Road after being diverted off Frame Drive.

Another issue raised in council was about Metcalfe Lane - which runs parallel to Gingers Lane, is unsealed and could become a ratrun while the detours are in place.

A report is set to come back to council outlining strategies to manage potential increased traffic on the lane.

Council said their view was that Metcalfe Lane needs to be maintained at its current level of usage.

Gingers Lane Community Group member Rob Martin said he didn't object to Metcalfe Lane being closed, he just wants council to be clear and let the affected residents know if that's the case.

Gingers Lane will not be widened entirely due to an endangered ecological community at the Frame Drive end.

Council says the species, which live in the eucalyptus forest at the western end of Gingers Lane, will be protected by minimising the impact of the road widening, with the use of current standard safety barriers.

An area suitable for widening will be used to create a breakdown/enforcement bay.