Proposed European Union plans to make scheme funding rules uniform across member states could force UK firms to pay off deficits faster, Towers Watson warns.
Today's Budget announced contracting-out for defined benefit schemes would be scrapped as part of the move to a single tier state pension.
Government has compounded the misery for final salary schemes by reducing the contracted-out rebate level, industry figures say.
Changes to defined benefit indexation have saved FTSE100 schemes more than £15bn, Towers Watson estimates.
Pension increases will fall by almost one-third next year as a result of the switch from RPI to CPI indexation, Towers Watson analysis reveals.
Reducing the annual allowance to as little £30,000 could affect thousands of additional pension savers, consultants and advisers say.
Liberal Democrat tax policy would result in some people paying more tax over their lifetime if they contribute to a pension, Towers Watson says.
A Labour manifesto commitment to increase the basic state pension in line with earnings from 2012 will cost £2bn a year by the end of the next parliament, Towers Watson warns.