Larry Fink told delegates at a pensions conference in Edinburgh yesterday that workers should not have the right to opt out of employer schemes as they can presently. He said allowing this meant many would not put enough money away to fund their old age.
Mr Fink said: "I would recommend simply making an appropriate level of retirement savings mandatory here in the UK, without the opportunity to opt out. There is too much risk that people will either opt out, or not put enough away even if they remain in a plan."
Britain introduced automatic enrolment of workers on to company pension schemes in 2012 but allows people to opt out.
His views echo the findings of a report by right-leaning think tank Policy Exchange. It said 40% of working Britons, 11 million people, were in danger of not building up big enough pension pots to ensure a comfortable old age.