The federal government is steadfastly refusing to defend or express an opinion about last week's decision to cut penalty rates, despite urging business to get on the front foot and sell the economic benefits of lower weekend wages.

Senior sources denied the government was leaving itself wriggle room to overturn the decision should political pressure become too great, arguing that its attitude to the Fair Work Commission decision was consistent with its position on the independence of the Reserve Bank of Australia and the Federal Court.

As the government sat on the fence, small business ombudsman Kate Carnell, a former chief executive of the Australian Chamber of Commerce and industry, said "the last time small businesses tried to stand up and have their voices heard on penalty rates, they got absolutely poleaxed by the unions who stopped at nothing to attack and intimidate hard working mum-and-dad small business owners".

Small buisness ombudsman Kate Carnell says why would businesses subject themselves to 'thuggish union bullying again?' Vince Caligiuri

Referencing ACCI's 2015 Too Big to Ignore Campaign which highlighted Easter penalty rates, Ms Carnell said businesses that participated were singled out.

"War was waged against small businesses online, but more alarmingly, at their front door; there were instances of businesses being graffitied, while others had big tattooed blokes standing out the front of their shop intimidating the owners, their staff and patrons; it was horrible and bloody scary for those involved," she said.