Yes, if it is written into your contract, your employer may (within limits) be able to specify how you dress at work.
Your contract, and associated documents such as the staff handbook, may state that you need to dress in a certain manner, or wear a uniform.
Your contract might state that you need to dress 'smartly', rather than specifying any particular garments. As you might well have conflicting ideas of what counts as 'smart', you should ask your employer for clarification.
Your employer should try to avoid including elements in a dress code which would unjustifiably conflict with someone's religion or religious beliefs. For example, a dress code forbidding headwear would discriminate against male Sikhs who must wear a turban.
An employer may not specify dress conditions that discriminate between men and women.
