Short answer. No, not if the work says otherwise. Article 280 of the Labor Code says an employment is deemed regular where the employee performs activities usually necessary or desirable in the employer's business, regardless of the oral agreement of the parties. What you actually do determines your status, not what your boss called it out loud.
What the law says
The provisions of written agreement to the contrary notwithstanding and regardless of the oral agreement of the parties, an employment shall be deemed to be regular where the employee has been engaged to perform activities which are usually necessary or desirable in the usual business or trade of the employer
Labor Code, Article 280 — Regular And Casual Employment. Read the full provision →
The label does not control the outcome
Article 280 states that the provisions of written agreement to the contrary notwithstanding and regardless of the oral agreement of the parties, an employment shall be deemed to be regular where the employee has been engaged to perform activities which are usually necessary or desirable in the usual business or trade of the employer. Notice the phrase covers both written and oral agreements to the contrary. Even a written contract calling you "casual" would not override this rule if it does not fit the facts — a verbal statement carries no more weight against it than a written one would.
What actually decides your status
The test the article applies is about the work itself: whether you have been engaged to perform activities usually necessary or desirable in the usual business or trade of the employer. If the tasks you actually do fit that description, the law treats the employment as regular regardless of what you were told when you were hired. Your boss's spoken characterization of the job as "casual" does not change what the work objectively is.
The two situations the rule does not reach
Article 280 excepts employment fixed for a specific project or undertaking the completion or termination of which has been determined at the time of the engagement of the employee, and work that is seasonal in nature for the duration of the season. If your job genuinely fits one of these two categories, this particular rule about necessary-or-desirable work would not automatically make you regular, so it is worth being clear about which category your actual engagement falls into.
A separate path to regular status: one year of service
The article adds one more route regardless of the nature of the work: any employee who has rendered at least one year of service, whether such service is continuous or broken, shall be considered a regular employee with respect to the activity in which he is employed and his employment shall continue while such activity exists. So even someone genuinely hired as casual becomes regular, for that activity, once they reach a year of service — another point at which the verbal "casual" label stops determining the outcome.