The Cranbourne property owners, represented by legal firm Slater & Gordon, are seeking compensation from the council and 11 other defendants, including the Environment Protection Authority and the council's insurer the Municipal Association of Victoria.

If the talks set down for September 8 and 9 fail to reach a conclusion, the residents will proceed with a lengthy, costly litigation, says Manisha Blencowe, an associate at Slater and Gordon.

Ms Blencowe said she believed the 30 households evacuated in 2008 had all returned to their homes.

"Some were out for a few days, some for a period of months.

"A recent relocation was made when alarms went off in a house which required works to be undertaken.

"They are the only householders I'm aware of who have [recently] evacuated their house."

Ms Blencowe said a mediation session in March failed to reach a conclusion.

"If we fail to reach a conclusion again we'll prepare our plaintiffs for litigation proceedings against the 12 defendants. It will be a lengthy and costly fight that will involve a lot of witnesses and experts to front up to court."

Casey councillor Kevin Bradford said Brookland Greens residents were selling houses for less than their true value.

"Residents want the council to fix the problem so the issue can die away. It affects their quality of life, with also the inconvenience of having contractors coming into their home at all hours of day and night to check gas meters."

Casey Council's corporate services director Steve Dalton said the City of Casey was hopeful of reaching a resolution at the mediation hearing.

■ The bill for clay capping at the Stevensons Road landfill site has almost reached $5million after Casey Council approved another $480,000 for drainage works.

The council varied its existing contract with Goldsmith - Civil and Environmental, which is carrying out works on the site rather than bringing in another contractor.

The works will include the construction of drains above and below the ground retention system and will include upgrades to drains in Stevensons Road.