Pension rules for police widows in Wales and England have been called "antiquated" and "manifestly unfair".
Under current rules, some widows and widowers can lose their pension if they remarry or live with a new partner.
Mel Jones, of North Wales Police Federation, has called for regulations to be brought into line with Northern Ireland, which grants all police widows a pension for life.
It comes as a petition on the issue has attracted more than 115,000 signatures.
In 2015, the rules were changed by the UK government to allow widows of police officers killed in the line of duty to receive their pensions only if they remarried or moved in with a partner after 1 April that year.
But Mr Jones has called for widows or widowers who lost a spouse from 1 January 1989 to be paid retrospectively, like they are in Northern Ireland.
"The present system is antiquated, it needs reforming. It's potentially clearly unfair for individuals, depending on which police service they have served in," Mr Jones told the Newyddion 9 programme.
"They could have served in Northern Ireland, Scotland or England and Wales, and the rules are totally different for each country.
"Sadly, it's widows or widowers who are made to make a very difficult choice then. If they want to move on, remarry or live with somebody, they face losing their widows' pension."
Debra Poole, from Sarnau, Ceredigion, was widowed when her police officer husband, Russell, died nearly 15 years ago.
She receives about £900 each month and said she "could not have existed" without the pension as she was left to bring up their three young children on her own.
But she has criticised the current regulations, saying they force widows to "choose between love and money".
"If I choose to find another person, to love again, then my money will be taken from me," she said.
"My husband did work, he retired, he quite often put his life on the line for the job. He loved his job, but he also paid 11% of his pay every month for his pension and for his family.
"So I do feel that this is wrong. We're only seeking parity with the Northern Ireland ladies - our sisters we call them."
In response, a Home Office spokesman said: "This government has made clear its commitment to ensuring that public service pensions are affordable, sustainable and fair.
"That is why we brought regulations into force at the start of last year which mean that widows, widowers and surviving civil partners of police officers who die on duty in England and Wales, no longer lose their survivors' benefits if they remarry, form a civil partnership or cohabit."