Canadian dollar-store operator Dollarama Inc reported a bigger-than-expected rise in first-quarter profit, helped by higher sales and margins, and slightly raised its margin forecast for the year.

The company raised its earnings before interest, taxes, depreciation and amortization (EBITDA) margin forecast for fiscal 2017 to 21.0-22.5 per cent from 20.5-22.0 per cent.

Dollarama, which sells items for up to $3, said items priced higher than $1.25 accounted for 60.5 per cent of sales in the first quarter ended May 1, up from 55.8 per cent a year earlier.

That helped the retailer boost its gross margin to 37 per cent in the quarter from 36 per cent a year earlier.

The Montreal-based company's profit rose 28.4 per cent to $83.2 million, or 68 cents per share.

That beat analysts average estimate of 63 cents, according to Thomson Reuters I/B/E/S.

Dollarama's sales rose 13 per cent to $641 million. Same-store sales growth, however, slowed to 6.6 per cent from 6.9 per cent.

The retailer said it opened eight new stores in the first quarter.

Up to Tuesday's close of $92.59, Dollarama's shares had risen nearly 30 per cent in the past 12 months.