The Welsh Government is to press ahead with plans to increase the number of Senedd members despite opposition from senior Conservatives.

The reforms, proposed by Labour and Plaid Cymru as part of a co-operation agreement, would see the number of members increase from 60 to 96.

Currently the Senedd remains smaller than its other devolved counterparts with the Scottish Parliament having 129 members and the Northern Ireland Assembly having 90.

A Senedd committee has backed the changes saying a strengthened parliament would result in more powerful scrutiny of government and better representation of people in Wales.

Welsh Tories have called for the expansion plan to be put to a referendum, with party leader Andrew RT Davies calling it a “waste of both time and money”.

The committee also recommended the Senedd become the first UK parliament to introduce a gender quota.

A reform Bill could be introduced as early as next year with the aim for it to receive Royal Assent by May 2024, after which a boundary review would take place with the aim for it to be completed by April 2025, prior to the 2026 Senedd elections.

The chairman of the special purpose committee on Senedd reform, Huw Irranca-Davies, said: “Our report sets out a plan for a strengthened parliament which will provide a stronger voice for the people of Wales.

“Today’s Senedd is very different to the institution that was established over 20 years ago. Its powers have increased to meet the ambitions of our modern and proud nation. It can now make laws and set Welsh taxes, issues which affect the lives of every single person in Wales.

“With greater powers must come greater accountability. We need a parliament that can effectively scrutinise the decisions taken by the Welsh Government, on behalf of the public it serves. The current system doesn’t allow that to be done as well as it should be.”

Mr Irranca-Davies added: “By leading the way on gender quotas, it will mean women – a majority group in Wales – will have certainty of fair representation, which can only lead to better and fairer outcomes for us all.”

The report provides detailed proposals for a new electoral system in Wales, including recommending closed proportional lists are used and that seats are allocated using the D’Hondt system.

According to the document, there should be 16 new Senedd constituencies and each should have six members.

The Welsh Conservatives have long opposed the plans, claiming the move could cost taxpayers up to £100 million over the next five years.

The report estimated the additional 30 MSs would cost around £12 million per year.

Shadow minister for the constitution Darren Millar, who resigned from the committee in protest, said: “Wales needs more doctors, dentists, nurses and teachers, not more politicians in Cardiff Bay.”

Leader Mr RT Davies said: “What are Labour doing to tackle cost-of-living pressures? Bloating the size of the Senedd at the taxpayer’s expense. That’s money that could be spent helping to alleviate the pressures household budgets are under.

“Even if you agree with more politicians, it can’t be right that Labour and Plaid are dictating the constituencies where people cast their votes. It reeks of pork barrel politics for electoral gain.”

A debate on the report’s findings is set to take place on June 8.