Thousands of 16 and 17-year-olds are yet to register to vote in the Welsh Parliament election, according to campaigners.

The Electoral Reform Society (ERS) said as few as 33% of people aged 16-17 in one area of Wales have registered to take part in the May 6 poll.

The Senedd election is the first national elections in Wales where 16 and 17-year-olds, as well as foreign nationals living in the country, will be allowed to cast a vote.

Around 70,000 people in the age group are eligible to register after the voting age was lowered last year.

In March 2020 the Welsh Government said research it commissioned showed young people and foreign citizens were more interested in voting in local elections than some groups of adults already enfranchised.

It said the results informed the work to change the eligibility requirements for who can vote in future Senedd and council elections in Wales.

When the Bill to lower the voting age was first introduced in the Senedd in February 2019, the presiding officer of the-then Welsh Assembly Elin Jones said she hoped it would "engage young people in particular in the democratic process".

But with the deadline to register looming on Monday, April 19 at 11.59pm, the ERS said figures from six counties show there is a postcode lottery on voter registration.

As of April 13 an estimated 33% of 16 and 17-year-olds were registered in Swansea and 35% in Neath Port Talbot, compared with 65% in the Vale of Glamorgan.

An estimated 41% in Pembrokeshire, 57% in Conwy, and 58% in Denbighshire were registered from the 16-17 age group.

Jess Blair, director of ERS Cymru, said: "The estimates appear to confirm fears that thousands of 16 and 17-year-olds are at risk of not having their say on 6th May.

"The Senedd elections represent a huge opportunity for young people to make their voices heard on a range of issues that affect their lives including education, health and the economy.

"The extension of the franchise to 16 and 17-year-olds should be a historic moment for Wales, but to make that happen 16 and 17-year-olds need to register and turn out to vote."

Ms Blair also called on the Welsh Government "to stop this postcode lottery" by bringing in automatic voter registration.

"Voting is a right, and you shouldn't have to opt into that, or get caught up in bureaucracy each election. Let's bring the system into the 21st century so everyone is able to speak up," Ms Blair said.