The prime minister has delegated that sometimes controversial duty to his senior public servant, the clerk of the Privy Council.
The unannounced move — made last June — followed revelations of large hospitality expenses approved by Harper himself in the months before.
The prime minister's pre-approval was given for an estimated $22,000 hospitality bill in late 2011 for visiting European bureaucrats, for example, at a time of federal belt-tightening.
The final hospitality costs for the three-day Ottawa event — including alcohol — were lower than expected, at $16,000 for 45 people, 10 of them Canadian public servants.
The year before, The Canadian Press reported that Harper personally approved a $7,400 bill for "refreshments" at a town hall meeting of public servants. The $42,000 event was held at the posh Westin Hotel, where meeting rooms cost $5,000 an hour.
Under the previous protocol, Harper was required to pre-approve all hospitality costs in excess of $5,000, under a government-wide directive to all ministers.
But Treasury Board rules also allow a minister to delegate the authority to a deputy minister.
Wayne Wouters, clerk of the Privy Council, now has signing authority, and must report his approvals on amounts over $5,000 to Harper every six months.
In the first six months after getting signing authority, Wouters reported, he approved $43,550 in hospitality at three events, including a whopping $27,000 for a four-day international spy conference in May, 2012.
Total costs for the International Intelligence Review Agencies conference, held in Ottawa for 60 delegates, ran to $136,000.
The Canadian Press obtained hospitality-related documents under the Access to Information Act.
A spokesperson for the Privy Council Office, Nicolas Boyer, did not respond directly when asked why Harper chose to delegate his authority, saying only that it was "permitted under government policy."
Boyer also said hospitality costs at PCO have fallen to $171,524 in 2012-2013, from $303,039 during Harper's first full year in office, 2006-2007.
"The government has tightened rules around hospitality spending to ensure accountability and respect for taxpayer dollars," Boyer said in an email.
A Treasury Board official, Pierre-Alain Bujold, said the government tightened the rules for hospitality in October last year to "expand the scope of expenses that fall under hospitality costs for an event."
The Harper government has twice previously moved to tighten hospitality rules, in the 2009 budget, which imposed a two-year freeze on spending levels; and in 2011, when other restrictions were imposed.
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