Wales’s Senedd has voted in favour of implementing Westminster’s assisted dying bill, overcoming a constitutionally awkward situation that could have forced terminally ill people who wish to end their lives to travel to England or seek private provision.

In a debate stretching into Tuesday night in the Senedd’s newly expanded chamber, members voted 28 for and 23 against, with two abstentions. Should the legislation pass the House of Lords, the matter will require another Senedd vote after May’s Welsh elections.

Tuesday’s legislative consent memorandum, a Senedd process used when UK legislation touches on devolved matters, was not a vote on the legitimacy of the bill. Instead, members voted on elements of the law – essentially, whether the service should be available on the Welsh NHS.

The vote, as well as its timing, was unusual. Labour, Conservative and Plaid Cymru members were given a free vote, making it difficult to predict the outcome. The Senedd rejected assisted dying in principle in both 2024 and 2014, with many abstentions.

Several members also said the vote should have been held until after the bill has made its way through the House of Lords, when it would be clearer what Wales would be consenting to.

In a vote last year, the House of Commons did not allow the Senedd a veto on whether assisted dying should be legal in Wales. The Welsh government said that holding the vote now was an opportunity to influence amendments under debate in the Lords.

In Scotland and Northern Ireland, criminal law, which includes suicide law, is devolved. In Wales it is not, a constitutional headache which experts say has created one of the worst criminal justice systems in Europe.

Several Senedd members raised ethical objections to the bill in Tuesday’s debate, but many also stressed they would vote against it because of the sovereignty issues it raised. A Plaid Cymru amendment criticised “the lack of thorough consideration of the constitutional implications of this bill for Wales”.

The MS for Carmarthen East and Dinefwr, former Plaid Cymru leader Adam Price, said that the motion put the Senedd in an “invidious position”, but withholding consent would “abandon Wales to a private only system” and a version of assisted dying which is “lawful but unregulated, available to some but not to others, and severed from the structures and services that we use to care for people at the end of their lives.”

Before the debate, the Welsh health secretary, Jeremy Miles, said that if the Senedd rejected the legislation, private providers may have been able to offer assisted dying services in Wales, or those seeking to end their lives would have to travel to England to do so.

Landmark legislation allowing terminally ill people in England and Wales to obtain a medically assisted death was passed by MPs in November. However, more than 900 amendments have been proposed by peers in the Lords, making it unclear whether the bill can pass both houses before its May deadline, when the current session of parliament ends.