The sentence for an ex-assembly member convicted of making indecent images of children as young as six has been labelled "ridiculously lenient".
Former Plaid AM Simon Thomas admitted making more than 500 illegal photographs and 77 films and was given a 26-week suspended jail sentence.
Welsh Conservative AM Andrew RT Davies is urging the Attorney General (AG) to review the case.
But the AG said the scheme to review sentences was not applicable.
"The Unduly Lenient Sentencing scheme only applies to specified offences and this offence is not currently within the scheme," a spokesman said.
Mr Davies said: "This sentence is absurd given the horrific nature of the crimes."
Thomas, who had also been the MP for Ceredigion between 2000 and 2005, quit the Senedd and his party after being arrested in July.
Mold Magistrates' Courts heard the indecent photographs were found on his tablet and mobile phone - which included almost 100 of the most serious category.
However, Judge Gwyn Jones decided not to impose an immediate custodial term.
Thomas was told he must also attend a rehabilitation course involving counselling and is subject to a sexual harm prevention order for seven years,
He was ordered to pay £85 costs and a £115 surcharge.
"You have lost your good character, you have caused a significant amount of pain and trauma to your family and, to put it bluntly, a significant fall from grace," added Judge Jones.
Defending counsel, Richard Williams said Thomas knew of "the problems that need to be addressed".
The NSPCC said Thomas' actions was not a victimless crime.
A spokesman said: "Within these images are young victims of abuse and by possessing them, Thomas has fuelled the demand in this awful trade."