Labor elder statesman Martin Ferguson says the ALP should support the return of the Coalition's construction watchdog, industrial relations reforms and warned Australia's high labour costs and low productivity risk billions in revenue.

In comments that will embarrass Opposition Leader Bill Shorten and ramp up political pressure on Labor to pass workplace law changes through the Senate, the former Rudd and Gillard government minister and ACTU president belled the cat on the Coalition's government's ''modest'' reforms to Fair Work laws.

Guess who?: Leaders of the House Christopher Pyne and Prime Minister Tony Abbott enter Parliament for question time on Thursday. Credit:Andrew Meares

Mr Ferguson's intervention comes as the Coalition introduced a raft of changes to the Fair Work laws to the Parliament on Thursday that tighten right-of-entry rules for unions, allow employees to trade penalty rates for more flexible hours and close so-called ''strike first, talk later'' loopholes.