CBCNews.ca will carry Harper's announcement live at 3:15 p.m. ET.
Sources tell CBC News that Harper's announcement, at a community centre north of Toronto, will cap the amount of tax savings at $2,000 per couple.
But CBC News has learned Harper is also expected to announce enhancements to the existing Universal Child Care Benefit, which currently gives parents $100 per month per child six years old and under, to increase the monthly amount and expand the age of eligibility.
Harper has already announced the federal children's fitness tax credit will be doubled immediately, to a maximum credit of $150 per child from $75, and made fully refundable as of 2015. A refundable credit means parents whose incomes are too low to pay taxes will still get money.
During the 2011 federal election campaign, Harper promised to introduce income splitting once the budget was balanced, a goal that will officially be met with next spring's budget and one that many observers believe is already a fact. The Conservatives said in 2011 the proposal would allow couples to transfer of up to $50,000 from one spouse or partner to the other to take advantage of lower tax brackets and would cost $2.7 billion.
Today's announcement is expected to put some limits on that original plan to reduce the cost of it and allow for other targeted tax breaks.
The New Democrats announced a $15-a-day child-care plan earlier this month as part of an ambitious plan to create or maintain a million affordable daycare spaces across the country.
Liberal Leader Justin Trudeau has already vowed he’d reverse a Conservative income-splitting policy if his party forms a government. Trudeau will speak to reporters after Harper's announcement.
More to come