MP Alun Michael believes children as young as 14 should get the vote.
Mr Michael, Labour's MP for Cardiff South and Penarth, has long been in favour of widening Britain's enfranchisement, saying young people are under-represented.
He argues that lowering the voting age by four years would increase voter turnout as well as encouraging youngsters to engage with politics.
His comments came in the wake of last week's local government election results, which had a turnout of 32 per cent.
Writing in his regular column in local newspaper the Penarth Times, Mr Michael said: "14 (is) an age which I find young people far better informed and sensibly engaged than was the case in the past.
"They will then know how to vote if and when they come to engage with political issues later in life.
"In the 2010 general election, only 44 per cent of those aged 18-24 voted, whereas 76% of those over 65 voted.
"There's only a 50/50 chance of first-time voters actually using their vote.
"Something surely needs to be done."
Eighteen is the most common age to be able to vote in countries across the world, but in the UK there have been growing calls for it to be lowered.
Earlier this year, a consultation exercise was launched in Scotland to canvass people's views about lowering the voting age for the forthcoming referendum on independence.
And in March, the Welsh Assembly's presiding officer Rosemary Butler called for a debate on lowering the voting age in Welsh elections to 16.
Campaign group Votes At 16 said the current system left many young people under-represented in politics.
Liam Preston, 26, chairman of the British Youth Council, which is part of the Votes At 16 coalition, said: "I am delighted Alun Michael recognises young people are both better-informed and more engaged than they were in the past.
"Locking young people out of the political system is patronising: it relies on out-dated views about young people's capacities.
"One hundred years ago, people thought that women should not get to vote, and in 1970, the voting age was lowered from 21 to 18."