Labour's manifesto pledge to reduce the voting age from 18 to 16 in UK general elections has not been included in the King's Speech.
But Commons leader Lucy Powell told the OceanNewsUK for 16 and 17-year-olds remained a commitment, and she hoped they would be able to vote in the next general election.
During the recent election campaign, the Conservatives accused Labour of trying to "distort the political system" to entrench itself in power.
Forcing members of the House of Lords to retire at the age of 80 was another pledge which did not make the cut when King Charles read out the new government's planned laws for the new parliamentary session.
Then-Home Secretary James Cleverly warned that measures like extending the vote to 16 and 17-year-olds were an attempt by Labour to "lock in their power permanently, because they don't really feel confident they're going to be able to make a credible case to the British people at the next election".
Pressed on Radio 5 Live on why lowering the voting age had not featured in this King's Speech, Ms Powell said there were "plenty of big bills that didn’t make it into this".
An elections bill would come later in the parliamentary cycle, she promised, adding: "It's absolutely a manifesto commitment."
Asked if 16 and 17-year-olds would be able to vote in the next general election, she said: "I hope so. That's the intention."
A session of parliament often lasts for around a year - and there are several sessions in a full parliamentary term of five years.
People aged 16 and over can already vote inparliamentary and local elections in Scotland and Wales.
The speech did include some reform of the House of Lords - a bill to remove the right of the remaining hereditary peers to sit and vote in the Lords - but not to reform the retirement age.
An official briefing paper on the House of Lords (Hereditary Peers) Bill said that in the 21st century, there should not be nearly 100 places reserved for individuals born into certain families, with those seats in effect reserved for men.
Lords reforms under Tony Blair reduced the number of hereditary peers to 92. That was intended to be only a short-term compromise, but the arrangements have persisted for 25 years.
The King indicated that further constitutional changes were likely later in the parliamentary cycle.
The government would "strengthen the integrity of elections and encourage wide participation in the democratic process", he said.
A "modernisation committee" of the House of Commons would be tasked with "driving up standards, improving work practices and reforming procedures", he added.
The UK voting age was last lowered in 1969 - from 21 to 18 - by Harold Wilson's Labour government.
The age was reduced to 16 for elections in Scotland - by the Scottish Parliament - in 2015. A similar measure took effect in Wales in 2020.
