Prime Minister Malcolm Turnbull says "masses of evidence" exist to support a reduction to some penalty rates by the Fair Work Commission, saying the changes will see more businesses open on Sundays and public holidays, and lead to job creation.

Following days of criticism of the Coalition's response to pay cuts for workers in retail and hospitality, Mr Turnbull used a visit to a solar farm project in Queensland on Sunday to back in the move, in concert with Treasurer Scott Morrison and One Nation leader Pauline Hanson.

"We support the decision, we accept the decision, we recognise it was a careful decision and we respect it as decision of the independent umpire and there's masses of evidence to support it," Mr Turnbull said.

"The point about about the decision of the Fair Work Commission, which was very carefully considered, is that it will generate more jobs, more employment ... that will be a very significant benefit for the economy.