Lord Garel-Jones was born in Wales but moved away aged six
People of Welsh descent around the world should have a vote in any referendum on more powers for the assembly, an ex-Tory minister says.
Lord Garel-Jones said Welsh people who live outside the country, but who have a family connection with Wales, should be given a say in its political future.
He made the recommendation to the All Wales Convention, which is considering arguments for more assembly powers.
But political experts say his idea would not work in reality.
Lord Garel-Jones, who was born in Wales but has lived in England and Spain since he was six, handed in a submission to the convention, signed by "eminent" Welsh people who live and work in England.
He told BBC Wales' Dragon's Eye programme: "If you are, I think the term is patrial, if you have a patrial connection with Wales, and you feel, as I do, and I think most of the signatories to this submission do, a certain emotion about your own country, then I think if big decisions are being taken, it wouldn't be inappropriate for us to have a vote.
"Inside the European Union, there are at least eight or nine countries where people who are not resident in the country are entitled to vote."
Lord Garel-Jones, who held the position of Minister of State for Europe from 1990 to 1993, said it would be a matter for the assembly government how the Welsh connection could be interpreted or defined.
He said: "Clearly one wouldn't want to reach the point where a couple of hundred thousand people in Southern Argentina, who left Wales in 1850 were voting, but I think if the principle of Welshness is accepted then I think it would be good."
But Glyn Mathias, the former Welsh Electoral Commissioner, said he did not believe Lord Garel-Jones' recommendation would work.
"It's an interesting idea but in reality you have to stick to the normal franchises," he said.
"I think any referendum would have to be held under the normal franchises that are held. In other words, the voters who are on the electoral register."
Fellow Conservative David Davies, the MP for Monmouth, added: "I think Lord Garel-Jones is a wonderful guy but I wouldn't necessarily agree with him this time.
"I can see where he's coming from but wouldn't really go along with that."
The All Wales Convention is considering arguments for and against further powers for the Welsh assembly.