Wales defence coach Shaun Edwards has told wing George North that he cannot afford to let his performance levels drop if he is to retain his place in the side.

The 24-year-old came under fire for his defensive showing against Scotland last month, as the Dragons collapsed in the second half to fall to a second defeat in three Six Nations outings.

Ahead of Friday evening's meeting with Ireland in Cardiff, Edwards has issued a warning to North and expects him to take the message fully on board should he be given the nod by stand-in boss Rob Howley.

"If he is selected, I expect George to certainly be on his mettle," he told reporters. "I also think that George had a very good game against Italy, in very, very difficult circumstances. He got a really bad bang on his leg and toughed it out well.

"Yes he wasn't at his best against Scotland but I think great players, who've done great things for you in the past, sometimes deserve a warning."

Wales are currently fourth in the Six Nations standings after three rounds of fixtures, eight points adrift of leaders England and five off next opponents Ireland in second.