According to Way Fund Managers, whichever party comes into power at the next general election will use the tax as a "golden goose".
Chairman and technical director Paul Wilcox questioned whether the Conservative Party's pledge to raise the threshold for inheritance tax to £2 million is realistic.
He advised homeowners to ensure they retain access to their assets and warned against being complacent in the light of falling property values.
"Given the likelihood of a major recovery in share values a couple of years down the line, now is the time for investors to move assets out of their estates and start the seven year clock ticking," said Mr Wilcox.
Last month Peter Horn, senior adviser at Blevins Frank, warned that unmarried couples moving to France should be aware of the complicated inheritance tax laws there.
