The Daily Record reports that the title-chasing outfit reacted with fury after skipper Eric Milligan was pulled out of today's potential home league decider with Biggar -then reinstated after the intervention of SRU chief executive Gordon McKie.
Versatile front-row forward Milligan began his contract as a pro with the Warriors this week and had been released back to Hawks in the hope of helping them claim their third BT Premiership crown on the trot.
However, Hawks coach Davie Wilson reluctantly left the player out of his plans, claiming he had been ordered to use him as a specialist hooker and not in his usual prop role.
Club director John Roxburgh said: "Naturally we were delighted when Eric was given the go-ahead to play for us this weekend when the right sequence of results will enable us to retain the championship.
"But it was completely out of order for Hugh to stipulate what position he will play. He was being unnecessarily overbearing and showed little or no consideration for the player.
"I understand Warriors are looking to use Eric as a hooker. That's fine but our argument is that their next Celtic League match is not until February 18 and there is plenty of time for him to get up to speed in training.
"Our game preparations did not feature Eric as a hooker and we were not prepared to disrupt our plans, so we had little or no option but to leave him out."
The wrangle was referred to McKie, who ruled that Milligan should be involved in the Hawks match after all.
And because the order came so late the player will only be on the bench - and available to come on in any of the front-row slots.