Leaseholders in high-rise blocks of flats face paying £500 more every year in inflated service charges because of new fire safety rules, experts have warned.

The Fire Safety Act and Building Safety Bill has been designed to make sure the causes of the tragic Grenfell fire in 2017 are not repeated.However the measures – which include regular inspections of fire doors, compartmentation to isolate fires and employing building safety managers – will bring big extra costs for flat-owners in high rise blocks.The new measures would bring additional, long-term costs on top of the bills for external wall safety (EWS1) assessments and any remedial cladding works.Nigel Glen, of the Association of Residential Managing Agents, a trade body, said a service charge increase of £400 to £500 per leaseholder was likely because of the changes.

Mary-Anne Bowring, of Ringley Group, which manages 12,000 homes across Britain, called the Bill a “minefield” that would detonate new charges. She called for extra funding to cover the costs of inspections.Door inspections alone would likely cost £100 per leaseholder per year, Ms Bowring said, and rely on an inspector being able to access all flats on a single day to avoid spiralling costs.The Building Safety Bill requires the person accountable for a block to show they have tried to recover costs from the party at fault. However, this has become an issue for older blocks, where accountability has been difficult to prove, said Mr Glen. Leaseholders could have to pay between £25,000 and £40,000 just to find out who is responsible, he said.The new charges come after thousands of leaseholders forked out for EWS1s that, in many cases, are no longer needed. In July, the Government U-turned on its stance they were required for buildings below 18m tall. Ms Bowring said one block with 88 leaseholders –had paid for two EWS1s that are no longer required. “They have wasted nearly £20,000,” she said – £220 per homeowner.

Cladding costs have meant some residents can no longer afford to maintain their buildings. “They are falling into a cycle of decay because there are no reserve funds,” Ms Bowring added.A Government spokesman said resident safety was its number one priority. He added: “We are delivering a programme of legislative reform through the Fire Safety Act and Building Safety Bill as well as considering responses to the Fire Safety Consultation. We have committed to laying secondary legislation in the autumn.”

He said that the Government had made £5bn available to remediate unsafe cladding from buildings 18m or higher and that EWS1 forms were not a Government process.