How important is a certification in project management for securing a related job? does experience carries weight in project management?

A certification is a proof that the person has enough knowledge about a certain aspect, yet, knowledge and experience are two different things that complement each other, therefore, the experience bit plays a vital role of getting you employed, and how you can stand out from the rest is obtaining a Project Management certification to prove your knowledge of the international guidelines.
From experience, there are non-certified professionals who are as competent as those who have the certification (sometimes better), but, employers need guarantees, and that is what professional certification would add.

It would depend on when the certificate was obtained and what industry you are in.
I personally am fining it difficult to obtain a position in the UAE as I have no Degree in my field and most employers seem to require one, despite my17 years experience at the top of my field and a long list of vocational certifications - however any Degree I may have gained would be15 years old and most of the knowledge imparted would be hopelessly out of date by now as technology and processes have changed a great deal in this time, so there are times when this is a very short sighted position for an employer to take.
It is however understandable, as it is difficult to correctly assess a persons competency simply from the experience they say they have - what is most important is to judge what a prospective employee has gained from this experience, if like myself they have a personal commitment to lifelong learning and self assessment and their experience is gained in a quality environment then it is worth far more than any certification, however this is not always the case.

Getting certified plays a role in giving you a better chance of being noticed for a related job.
Having the experience, of course, plays the major role.
Think of experience as the "cake" and the certificate as the "topping." You can present the "cake" without the "topping" but you can't present the "topping" without the "cake." But the "cake" always looks better with the "topping."