Northern Ireland midfielder Corry Evans has apologised after an offensive message aimed at Romanian referee Ovidiu Hategan was posted from his wife's Twitter account.

Evans conceded a crucial penalty for handball in his side's 1-0 loss to Switzerland in the first leg of their FIFA World Cup play-off in Belfast on Friday (AEDT).

But the award of the spot-kick was highly controversial, with Evans appearing to block a shot from Xherdan Shaqiri with his side as he turned away from the ball.

Northern Ireland coach Michael O'Neill called the decision "staggering" and his team will now have to try and turn the tie around in Monday's (AEDT) second leg in Basel.

Evans's wife Lisa reacted to the decision by posting a message on Twitter that included xenophobic terms and insults. The post was later deleted.

Blackburn Rovers midfielder Evans, who will miss the second leg through suspension, issued an apology through the Irish Football Association (IFA).

"On behalf of my wife, I would like to apologise unreservedly for the content and language contained in the Tweet that she issued last night," Evans said.

"The comments were published in the heat of the moment and are not representative of her views."

His wife also posted an apology on Twitter, which read: "I would like to sincerely apologise to anyone I offended for the language contained in my tweet, I understand it was completely unacceptable, I should have never have let my emotions take over. I would never condone racism in any way."