Cancer specialist Baroness Finlay of Llandaff is attempting to allow smoking in public places in Wales to be banned.
Baroness Finlay's bill is unlikely to become law
She has launched a bill in the House of Lords which would give the assembly the power to outlaw lighting up in pubs and restaurants.
Her proposed legislation, the Smoking in Public Places (Wales) Bill, would need active support by health ministers and the Welsh assembly to become law.
To date, the government has preferred to rely on voluntary curbs on smoking by public places of entertainment, and the bill is unlikely to enter the statute books.
The bill is receiving its first formal reading on Thursday evening in the Lords.
The baroness told News Online she had decided to introduce the bill in order to give the assembly the option of banning smoking in public places if it chose.
She said: "The assembly themselves had voted last year to do this but they need empowering legislation.
"I wanted to empower them to do what they have said they want to do.
"I'm not imposing anything on Wales, I'm only letting the assembly do what it wants to do."
"[Health Minister] Jane Hutt is trying to do her best to improve the health of the nation."
Baroness Finlay added: "It also raises constitutional questions if the government doesn't let the assembly do what it wants to do with a devolved issue like health."
She said her bill had come just after the Royal College of Surgeons highlighted the dangers of inhaling others' smoke and said banning smoking in public places could help take away peer pressure some felt to light up.
Baroness Finlay is the vice-dean of the School of Medicine at the University of Wales, Cardiff and a professor of clinical work at the Velindre Cancer Centre.
She is recognised as an expert in the field of palliative care and was made a baroness in 2001 in recognition of her work.
To date, it is the USA which has gone the furthest in stamping out cigarettes in public.
Although there is no national legislation banning smoking, various states such as California and Delaware, and cities like New York and Honolulu, have banned smoking in bars and restaurants.
The arguments for the ban centre around protecting the health of employees.
In Europe, Norway is set to bring in an national ban on smoking in bars and restaurants next summer, while Ireland is banning smoking in the workplace from February 2004, which will cover pubs and food outlets.