Elfyn Llwyd MP, who led a parliamentary inquiry on stalking, accused prosecutors of "undercharging" and called for a change in culture in the CPS and police, claiming stalking is too often treated as a domestic issue.
The Plaid Cymru Westminster leader said charging lesser offences often ends with a "slap on the wrist" and do provide justice for victims.
"We need to so make sure prosecutors take this very serious offence as they should because it is a considerable area of concern." Llywd said.
More top news
Through the day, most of the cloud should break up to leave fine conditions for many with spells of sunshine.
The Eiffel Tower in Paris was plunged into darkness, with the Burj Khalifa in Dubia emblazoned with the Union Jack.
The major party leaders' campaigns for the General Election will remain suspended on Wednesday following the Manchester terror attack.