Retired Melbourne skipper Cameron Smith says the behaviour of his former teammates is "mind-boggling" after star duo Cameron Munster and Brandon Smith fronted the NRL integrity unit following a leaked party video.

The long-time club leader lashed the players, as well as Storm forward Chris Lewis, who were hauled in on Tuesday while the club conducts its own investigation.

The NRL is expected to suspend the players for at least two games and hand down fines of up to $40,000.

Two undated videos surfaced online early this week that appeared to show Munster, Smith and several other people in a room with a white substance on a table.

A second video shows Munster dancing on the same table.

Lewis, who made his NRL debut last year as a 28-year-old, isn't in the vision but is part of the probe.

Smith described the actions of the players, as "dumb" and said they had made a poor choice.

"I'd like to think they're smarter than the way they've acted.

"To allow outsiders into a room and they've got phones out filming … it's mind-boggling to see these guys make these poor choices."

He said Munster and Smith were Storm leaders and he was extremely disappointed by the way they had treated the club.

"They've put so much heat and spotlight on the Melbourne Storm as an organisation and the same on their teammates and former players … who for their entire career did the right thing," the former Kangaroos captain said.

"That's what annoys me."

Melbourne football boss Frank Ponissi told SEN radio the incident capped a miserable few days following their preliminary-final loss to Penrith.

"As a club we're bitterly disappointed with the incident," said Ponissi.

Ponissi, who joined Melbourne in late 2007, said the behaviour wasn't indicative of a culture problem at the NRL powerhouse.

"Any time there's an incident it's a problem but it's not widespread [throughout the club]," Ponissi said.

"It's probably how you react — any great cultures will face moments of adversity and challenging times … but it's how the people in the club react and we will react in the most positive way possible."

The Storm issued a letter to its members on Wednesday saying the trio were remorseful for their actions.

"Having spent a lot of time with the players involved over the last few days, I know they are extremely remorseful and embarrassed," Melbourne boss Justin Rodski wrote.

"We expect to be in a position to provide an update to our members early next week.

"The three players involved will also be present to address this issue directly once the investigation has concluded."

AAP