Negotiations will pick up again later this week when all three are freed from quarantine.
A source said it would now be autumn before a plan was announced to MPs in the Commons.
Professor Len Shackleton, Editorial and Research Fellow at free market think tank the Institute of Economic Affair (IEA), slammed the proposal as a “burden” on working age people.
Professor Shackleton explained: “Hiking National Insurance will be yet another burden on working age people at a time when jobs are insecure, inflation is rising and wages are squeezed. “Much of the public may believe that National Insurance pays for the NHS, and social care would just be a natural addition.
“But National Insurance is not ringfenced and is simply an income tax by another name, albeit with different exemptions, starting points and arbitrary changes in rates which don’t coincide with tax bands.