The Government is backing a Private Member's Bill making it offence for people to wear military medals they are not entitled to.
The Awards for Valour (Protection) Bill tabled by Conservative MP Gareth Johnson - which receives its Commons second reading on Friday - will create a new criminal offence with a maximum penalty of six months' imprisonment or a £5,000 fine.
Defence Secretary Sir Michael Fallon said he "fully supports" the proposed legislation.
"Medals recognise our forces who risk their lives for freedom. It is important their service is properly protected," he said.
Legislation making the unauthorised wearing of medals a criminal offence was originally introduced in the aftermath of the First World War by the then secretary for war, Winston Churchill.
It remained on the statute book until 2006 when the new Armed Forces Act came into force and the provisions relating to military decorations were not carried over.
Mr Johnson's Bill has already received the backing of the Commons Defence Committee, which said in a report earlier this week that the unauthorised wearing of medals constituted "a harm that is worthy of specific criminal prohibition".
"Such behaviour is not only insulting to the rightful recipients of these awards, but also damages the integrity of the military honours system and the bond of trust and respect between the public and the armed forces," it said.
"We conclude that there is a tangible and identifiable harm created by military imposters against members of society who should rightly be held in its highest esteem. Therefore, we believe that specific prohibitions to mitigate this harm are justified."