Former Victorian Premier and Beyond Blue ambassador Jeff Kennett has criticised Sydney siege survivors for selling their story, saying it devalues the lives of the two victims.

Mr Kennett’s comments on Twitter on Monday night were met with both praise and criticism, following reports siege survivor Marcia Mikhael had been seeking a six-figure sum for her story.

• Sydney siege hostage’s ‘six-figure’ interview
• Why hostages should be immune from criticism

“Is it not sad, those involved in the Sydney siege, who’s lives were saved are now selling their stories for profit. Terribly disappointing,” Mr Kennett wrote.

Is it not sad, those involved in the Sydney siege, who’s lives were saved are now selling their stories for profit. Terribly disappointing

— Jeff Kennett (@jeff_kennett) January 19, 2015

“I do not think it is morally right that the media pay, and any of those who were saved should profit from the attack. Just plain grubby.”

Some people agreed with the retired politician, saying survivors were making money from the death of Lindt cafe manager Tori Johnson and lawyer Katrina Dawson.

But not everyone agreed, one man tweeted, “If a few $$ somehow makes life easier to move forward it’s great”.

@jeff_kennett I’m not so sure. Easy to say if you’re financially comfortable. They suffered. And have a story to tell. — Bernie Quinn (@BQPtex) January 19, 2015

@jeff_kennett I disagree.Good luck to them!Their lives changed forever more.If a few $$ somehow makes life easier to move forward it’s great

— Peter Ford (@mrpford) January 19, 2015

@jeff_kennett I’m not sure.. Where is the line? Many fantastic books written about tragic events

— Bernie Quinn (@BQPtex) January 19, 2015

Last week it was revealed Ms Mikhael had offered to sell her story to The Australian, with her lawyer saying they would be “insulted” by a figure of $10,000, which was “not going to cut it at all”.

Ms Mikhael’s lawyer said the money would go to a foundation which is yet to be established.