Private-sector contractors and freelancers will not be fined for inaccuracies relating to the off-payroll working rules in 2020/21.
HMRC published a report into the changes, which kick in from April, and promised a light-touch approach to any errors in the first year.
The report says fines will only be issued where there is "evidence of deliberate non-compliance".
The Revenue will also "commission external research into the impacts of the reform six months after implementation", around October 2020.
Campaigners, however, have issued a predominantly negative response to the Government's verdict.
Directors have voiced concerns about a shortage of outside expertise available to them from April.
Tej Parikh, chief economist at the Institute of Directors, said:
"This offers cold comfort to businesses and the decision to press on with the changes in April will cause significant concern.
"Outside expertise and project-based work play an important role for many organisations.
"A light-touch approach to enforcing penalties will help, but many will be left wondering why the policy could not wait another year."
The Association of Independent Professionals and the Self-Employed (IPSE) went a step further, slamming the review as "recklessly inadequate".
Andy Chamberlain, deputy director of policy at IPSE, added:
"Not only was it not independently chaired, it was also rushed out of the door in less than two months.
"These tweaks go nowhere near far enough. If anything, this tinkering shows the Government knows the changes to IR35 will be immensely disruptive to business and contractors, but plans to forge ahead regardless."
Talk to us about the changes to IR35.