An adviser to union pension funds is calling on General Electric Co. to drop KPMG as its auditor after a series of accounting missteps and strategic blunders rattled investor confidence in the once–blue-chip company.

In a letter sent Tuesday to GE's lead independent director, CtW Investment Group urged the manufacturer to find a new accountant for the 2020 review and commit to changing auditors every 10 years. The group also is seeking stronger oversight of capital allocation following an “ill-considered buyback strategy'' and poor deal-making in recent years.

The renewed criticism of GE's accounting oversight piles pressure on the board a year after shareholders signaled displeasure with KPMG. While GE is keeping the firm for this year, the company said in December that it would solicit bids for a new auditor, opening the door to ending a relationship that has lasted 110 years. That's one of many shifts made by CEO Larry Culp as he tries to stem one of the worst crises in GE's 127-year history.