Deborah Cooper, partner at Mercer, estimated the cost to schemes from the ruling to be "in the region of £20bn".
Stephen Scholefield, partner at Pinsent Masons, warned "given the complexity, careful planning and good project management will be essential otherwise the costs of implementing the solution could cost more than the increased benefits that will now be payable."
Matt Davis, partner at consultancy Hymans Robertson, said he expected "millions of people will get extra pension" as a result of the ruling. But he agreed the methodology for making calculations was complex.
He said: "Calculations are being done on a year by year and case by case basis which will mean the ruling will have an impact on the industry for several decades.
"The complexity that will follow, in selecting and implementing the most appropriate method of equalisation will bring with it a series of additional costs that schemes will have to accommodate."