Photo: The Canadian Press

Prime Minister Justin Trudeau

Justin Trudeau will belatedly honour his campaign promise to cut the small business tax rate to nine per cent as his government scrambles to undo the damage from weeks of controversy over proposed tax reforms for private corporations.

The prime minister is to announce the reduction Monday, along with some changes to the tax reform proposals in a bid to re-establish the Liberals as the champions of middle-class Canadians.

That title has been tarnished in recent weeks as doctors, lawyers, accountants, shop owners, farmers, premiers and even some Liberal backbenchers denounced the reforms, contending they'd hurt the very middle class Trudeau claims to be trying to help.

The changes are expected to be largely technical in nature, aimed at more clearly targeting the reforms at wealthy individuals who've used incorporation of small businesses to gain what the government maintains is an unfair tax advantage.

They're also expected to address concerns the reforms will disproportionately impact women, inhibit the ability of small business owners to save for a rainy day and make it impossible for farmers, fishers and others to pass their businesses on to their children.

The addition of a cut to the small business tax rate appears to be the political equivalent of a spoonful of sugar to make the reform medicine go down.

Trudeau campaigned in 2015 on a promise to reduce the small business tax rate to nine per cent from 11 per cent over three years.

But in the 2016 budget, Finance Minister Bill Morneau froze the rate at 10.5 per cent and cancelled a legislated reduction to nine per cent instituted by the previous Conservative government.

Faced with an angry backlash to the tax reform proposals, the Liberal government is now reviving the nine per cent promise, a source, who was not authorized to speak publicly on the matter, confirmed Sunday.

Finance Minister Bill Morneau has acknowledged that changes are required to address the concerns his reform proposals have triggered.