Justice Minister Peter MacKay says he was showing support for an Afghan veteran when he posed for a photo at a Conservative Party fundraiser wearing a T-shirt bearing the logo of the National Firearms Association, a pro-gun lobby group.

The photo shows MacKay standing with two people and wearing a black shirt with the image of a maple leaf attached to a military-style assault rifle. The NFA's slogan — "No Compromise" — appears under the logo.

A similar photo was first posted to Facebook by the National Firearms Association earlier this week. (Facebook)

"A Canadian veteran wounded in Afghanistan approached me at an event in Edmonton, handed me one of his T-shirts and asked if I would pose for a photo," MacKay explained in an statement emailed from his office.

"Having spent a great deal of time with members of the Canadian Forces, I have never shied away from an opportunity to demonstrate my support for them and their families," MacKay said.

The photo was originally posted on the NFA's Facebook page and a different version was later posted by Ericka Clarke, an NFA field officer. She and MacKay appear in the photo with Kurtis Gaucher, who describes himself on Facebook as an employee of the Canadian Armed Forces and has been quoted as a veteran in numerous news articles. Gaucher, who did not respond to CBC News requests for comment via Facebook, also appears to be wearing an NFA lapel pin in the picture with MacKay.

Clarke told CBC News in a Facebook message that she had brought the T-shirt to the event.

"I brought the shirt and let [MacKay] keep it afterwards... I don't recall which of us handed it to him," she wrote.

'Glaring lack of judgment'

In a conversation on Twitter, Clarke suggested she explained to MacKay what it meant.

"I brought the shirt and Kurtis asked if he'd put it on. Then we chatted about what was on it before [the] picture [was taken]," Clarke wrote.

On Thursday, Clarke posted a link on Facebook to the NFA's store with a note saying "Come buy the most popular shirt in Canada!"

NDP Leader Tom Mulcair took notice of the photo and condemned MacKay for his actions.

"It sends the wrong message and shows a glaring lack of judgment," Mulcair said in a written statement to CBC News.

The Conservatives campaigned for years against the federal long-gun registry so despised by pro-gun groups and finally killed the registry in 2012, but have still faced pressure from pro-gun groups to curb restrictions on guns.

The government said last month it was loosening restrictions on some firearms while introducing new safety measures for gun owners. The proposed changes were published in the official Canada Gazette Aug. 15.

The MacKay photo has drawn some reaction on social media from both gun advocates and critics. View a Storify of some of the reaction below.

Mobile users, view the Storify here.