The Finance Department says the federal deficit was $2.9-billion over the first three months of the fiscal year.
The result compared with a $3.6-billion surplus for the same period a year earlier.
Program expenses excluding net actuarial losses for the April-to-June period totalled $107.5-billion, up from $93.8-billion for the same period a year ago.
Meanwhile, revenue amounted to $120.4-billion, up from $110.6-billion a year earlier, largely reflecting higher tax revenue.
Public debt charges totalled $13.9-billion, up from $10.7-billion a year ago, due to higher interest rates.
Net actuarial losses amounted to $1.9-billion, down from a loss of $2.5-billion a year ago.