Citigroup has warned U.K-based employees of the likelihood of redundancies as the lender pushes ahead with a sweeping reorganisation, according to a memo seen by Reuters on Friday, a move that could affect hundreds of jobs in the country.

The bank, which has about 16,000 employees in the UK, said it was moving into phase two of its plans to rationalise its banking structure and as part of that would set up a consultation process whereby employees can give their feedback.

"We anticipate that the reviews may lead to a reduction in roles in some parts of the business, and changes to some other roles. In some cases, colleagues may be placed at risk of redundancy," James Bardick, UK Citi Country Officer, told employees in the memo seen by Reuters.

The bank did not tell Britain and North Ireland-based employees how many jobs would be eliminated.

"As we take the necessary next steps to align our organization model with our strategy, we’re committed to following all legal and regulatory requirements and, importantly, supporting our colleagues through these changes," a Citi spokesperson said in a statement to Reuters. (Reporting by Anousha Sakoui; editing by Elisa Martinuzzi and Jan Harvey)