OTTAWA -- Parliament's spending watchdog says three federal measures to help low-income earners, families and seniors weather the economic shock from COVID-19 will cost over $8 billion.

The reports this morning from budget officer Yves Giroux say a special GST credit payment to 13.2 million people will cost $5.67 billion.

A top-up to the Canada Child Benefit in May to 3.4 million recipients will cost $1.9 billion, Giroux says, with the average payment estimated at $556.

And reducing by 25 per cent the amount seniors have to withdraw this year from registered retirement income funds will cost $506.5 million, the budget officer says.

The reports this morning come hours before Finance Minister Bill Morneau is to answer questions about federal COVID-19 spending measures from the House of Commons finance committee.

The federal government's economic response package to date is valued at more than $250 billion with just under half of that -- over $105 billion -- being direct financial aid for workers and businesses.

 Morneau said Wednesday that two of the measures would have a combined cost of $95 billion -- $71 billion for a 75-per-cent wage subsidy, and $24 billion for a direct benefit to workers who have lost their income due to COVID-19.

An analysis published Thursday morning by the Canadian Centre for Policy Alternatives estimated that 862,000 unemployed workers -- about one-third of the total -- won't receive aid from either the new workers' benefit, or employment insurance.

About 1.2 million Canadians were looking for work before COVID-19 forced an economic shutdown to curb the spread of the disease, the analysis said. The centre's senior economist, David Macdonald, said half of them were not eligible for EI and now they aren't eligible for the new emergency benefit because their employment didn't cease due to the virus.