Melbourne Storm's Christian Welch has been stood down for a COVID-19 breach on Queensland's Sunshine Coast that occurred just hours before a two-week quarantine was due to be lifted.

The Queensland Origin prop has been placed into isolation after he invited a guest to the team's hotel overnight, in violation of the code's strict coronavirus measures.

The club has confirmed Welch will not play in the team's match tomorrow night against the West Tigers and has been placed into isolation, away from his teammates.

Welch, 26, now faces the possibility of an NRL fine, similar to those imposed on Broncos players and staff who breached the code's COVID-19 rules earlier this year.

In a statement, Welch said he was extremely remorseful.

"I love this game and everything it has given me and I'm shattered that I have let everyone down," he said.

"Calling my parents to let them know about this was the worst phone call I've ever made.

"I know it's a privilege to play in the NRL and I want to apologise to all for any damage I have caused."

The Melbourne Storm squad has been based on Queensland's Sunshine Coast since July.

The current NRL bubble placed on the Storm players and staff was due to be lifted at midnight as they last had contact with a NSW team, the Rabbitohs, on September 4.

'We're incredibly disappointed'

Storm chief executive David Donaghy said the timing of the matter would form a large part of the investigation by the NRL integrity unit.

"As of midnight last night, they're effectively allowed to leave the premises and conduct themselves in non-quarantine protocols," he said.

"The time of the matter is important and they're some of the discussions that are going on.

"Everyone's fully across the requirements, the timeframes and what's expected of the group whilst they're in the bubble … I don't think there's any ambiguity around that."

The club notified both the NRL and Queensland Government of the potential breach early this morning.

Mr Donaghy said the club was also aware how tough the time away from Victoria had been on the entire team and staff.

"We're confident that there won't be a test result come back with anything other than negative, however that has to go through a process," Mr Donaghy said.

"We take any type of breach seriously, I think everyone knows the standards of behaviour we expect at our football club.

"It goes without saying we're incredibly disappointed, the player's really upset."

It’s understood Welch is negotiating an extension on his current contract with the Storm, after he knocked back a recent deal from St George Illawarra.