Fluffy owners will have to disclose status of their homes to visitors

The new rules will also force Fluffy owners who stay in their homes to pay for a new asbestos management plan and safety assessment every two years and to give Worksafe five days' notice of any work that penetrates a wall or ceiling cavity, as minor as replacing a power point.

The management plans must be done by February 1 2016, when the rules about informing visitors also take effect. The plans must repeated every two years, and also repeated after any damage to the house, such as a hole in a wall or a fire.

Asbestos assessors will assess each of the homes for access routes for asbestos fibres from the walls and ceiling, and decide whether heating and cooling systems must be sealed, whether sliding doors must be sealed and whether repairs are necessary to cornices or other parts of the home. The assessments and the work must be done by the end of July 2016, at owners' expense, with the Asbestos Taskforce estimating an average $1200 for the two-yearly assessments and $1500 a day for cleaning and sealing work.

Taskforce head Andrew Kefford, who wrote to Fluffy owners on Wednesday, said for some, the requirement would be as simple as locking the manhole to the ceiling, locking the subfloor, having warning stickers and informing visitors. For others, more significant changes could be required, such as sealing cavity doors and heating and cooling systems, depending on the level of contamination by asbestos fibres.

The regime would be driven by testing, he said. A cavity door in a new extension was unlikely to be a problem, but a cavity door with access to the Fluffy-contaminated ceiling might need to be sealed open. Cupboards might have to be sealed off. Heating and cooling ducts would be checked for contamination and for whether the air return was open to the wall cavity.

"In a house where there is not significant contamination inside then this obligation is not terribly onerous. In a house where there is, yeah it'll be hard," Mr Kefford said. "But my expectation is that for most of the properties for which this is relevant they're at the less contaminated end of the scale."

It extreme cases, it might not be possible to develop an acceptable asbestos management plan.

"In most cases, particularly the ones where the assessment has shown no fibres in the house, we don't expect there's going to be an enormous amount to do, but if you start finding significant contamination it may well be that it's not possible to develop a satisfactory plan," he said.

"...At some point the works required to seal up and minimise that future exposure risk will start contravening things in the building regulations about heating and ventilation and building work."

He stressed the overriding advice to owners was to leave the homes. Anyone who stayed would not be able to stay indefinitely and in the long term, all of the homes must be demolished. Owners have until June 30 to sign up to the buyback scheme. Owners who refused would be liable for all costs, including eventual demolition, Mr Kefford said.

By Wednesday, 769 of the 1021 Fluffy owners had accepted the government offer, with just one requesting a slightly longer settlement. The government is prepared to sign settlement dates as late as June 30, 2020 – but those who stay will have to comply with the assessment and remediation rules.

Of the 252 yet to sell, Mr Kefford said a number had been waiting for this week's regulations to find out what they would have to do if they chose to stay put. About 20 had refused assessments last year.

The addresses would also be publicly available from late June this year, when the government releases the full Fluffy list.