Travel Time Issue: Is it compensatable?

Hi guys, I'm a newbie here, I just want to seek for answer to our problem in the office...

I worked as a part of a team whose work is specializing in environmental testing/ sampling. Usually, we are sent to various customer company location and facilities to conduct our work, however my employer refused to pay our travel time covering going back from customer location to office.
Normally, our working time starts from 8 am to 5 pm, and most of the case when customer location is far distant from our office, we usually arrived at past 5 pm, (worse case scenario more than 1 hr)
There is also some cases that we are travelling at far provinces and it falls even Sunday.

My question is, do we have the right to ask for overtime pay for this travel time? Is there any provision in the labor law about this case?

nope. if it is before or after your usual working hours then travel time is not paid

I see, thank you sir,

how about if we are advised to travel during restday?

We usually have clients across the region and we travel a lot, does it fall into the same rule?

Hi.

Here, this might help you: http://www.pinoylawyer.org/t230-is-my-travel-time-compensable.