The Albanese government has agreed to almost 100 amendments to its shakeup of workplace laws, including surprise new union powers over pay and conditions that employers attacked as “deeply concerning”.

Workplace Relations Minister Tony Burke introduced 81 amendments to the Closing Loopholes Bill in the House of Representatives on Tuesday on top of a deal with the Greens to criminalise superannuation underpayments and stop employers using new arbitration powers to reduce workers’ conditions.