An updated funding code due in 2020 could add £100bn to defined benefit (DB) pension scheme deficits in the UK and cause employer contributions to double, KPMG analysis has revealed.
The new Code of Practice on Funding Defined Benefits is expected to contain a "comply or explain" regime that strengthens funding standards and reduces risk for members.
Schemes will also be tasked with setting low risk long-term targets and managing investment risks better, with a first glimpse of the new code promised by this summer.
KPMG warned that average pension scheme deficits could rise by 50% as a result of the changes, with employers put under increasing pressure to pay off liabilities quickly.
"But at the moment the details of the new code are sketchy," KPMG pensions partner, Mike Smedley, said. "The Pensions Regulator pledged to become clearer, quicker and tougher.
"The 2,000 pension schemes which are due valuations this year will have the difficult job of planning for new rules which won't be published before the summer."
Employers that rely heavily on investment returns could also be forced into even greater contributions, with deficits expected to be met more rapidly than under the typical seven-year plan.
But KPMG said employers would question whether higher cash contributions are the most effective way of protecting the scheme, particularly if it cuts investment in the business.
At the same time, trustees may come under pressure to implement ever more prudent investment strategies.
"As a result we expect to see more creative solutions to bridge the gap and more contingent funding arrangements as a substitute for cash contributions," Smedley continued.
"For those schemes and employers that were already struggling to make ends meet, the new rules are likely to add further challenges.
"Some schemes may find themselves with irreparable pension deficits and will need to consider alternative strategies."