Ireland prop Jeremy Loughman should not have been allowed to return to the field after suffering concussion symptoms against the Maori All Blacks, New Zealand Rugby (NZR) has concluded.

A review into the incident found the correct protocols were not followed due to a communication error.

Munster loosehead Loughman was filmed falling backwards as he attempted to return to his feet following a collision in the second minute of Wednesday’s 32-17 defeat in Hamilton.

The 26-year-old was temporarily replaced by Cian Healy but, having undergone a head injury assessment (HIA), came back on before being permanently withdrawn at half-time.

NZR medical manager Karen Rassmussen said in a statement: “As a result of this review, NZR believes Ireland prop Jeremy Loughman should not have been allowed back on to the field during the first half.

“While NZR stands by the HIA processes in place and is satisfied that player welfare is the number one priority for medical staff at the match, we have identified a gap in communications, which meant critical video evidence was not fully accounted for as part of the Head Injury Assessment process undertaken by the independent match day medical team.”

Loughman, who is yet to win a Test cap for Ireland, will not be involved in Saturday’s series opener against New Zealand in Auckland.

After the midweek warm-up match against the Maoris, head coach Andy Farrell said the player was taken off “as a precaution”.

Cian Healy, pictured, twice replaced Jeremy LoughmanCian Healy, pictured, twice replaced Jeremy Loughman (Brian Lawless/PA)

Progressive Rugby, a player welfare lobby group, said it was “deeply alarming” that Loughman was permitted to return.

New Zealand Rugby has vowed to ensure head injury protocols are adhered to for the rest of Ireland’s tour.

“We will be reinforcing the full HIA process and protocols for the remainder of the Steinlager Series to ensure video evidence is communicated more accurately between independent match day medical staff to enable them to make the right call with regards to player safety,” continued the statement.

Healy, who twice replaced Loughman, was later forced off by a leg injury, which was initially feared to be serious.

However, the 34-year-old Leinster player has been named on Farrell’s bench for this weekend’s Test opener at a sold-out Eden Park.