LONDON, March 21 (Reuters) - Britain's banks and other financial firms are boosting the number of women in senior management roles, but unless the pace quickens, it will take until 2038 to reach gender parity, the finance ministry said on Thursday.

The ministry's Women in Finance Charter was launched in 2016, with signatory firms committing voluntarily to raising the number of women in senior roles by setting their own targets.

The proportion of women in senior finance roles climbed to 35% in 2023, from 34% a year earlier, for a seventh straight year of increases, the ministry said.

Over 400 firms employing 1.3 million people have signed up to the charter.

"I encourage signatories to continue to actively pursue measurable and ambitious targets, and remain accountable for progress against them," junior treasury minister Charlotte Vere said in a statement.

"Whilst this progress is commendable, we need to move quicker: at the current pace, we won’t achieve gender parity until 2038," said Amanda Blanc, group CEO of insurer Aviva and a Women in Finance Champion, who was appointed to spearhead the charter's efforts.

Think tank New Financial, which co-authored the update, said the UK, global and investment banking sectors had the biggest roles to play in shifting the numbers for the whole industry, as did the largest employers.

"If these firms can set a sustainable course towards parity, the face of the entire industry will change," New Financial partner Yasmine Chinwala said.

Parliament's Treasury Committee said in its report on Sexism in the City earlier this month that the charter's scope was too narrowly focused on senior management, and needed to include talent to support long-term improvements in diversity.

The lawmakers recommended that the charter's aim of linking executive pay to delivering diversity targets be made on a "comply or explain" basis, meaning boards would have to explain publicly if this commitment was not being adhered to.

(Reporting by Huw Jones Editing by Bernadette Baum)