Airport safety staff in Portuguese airports went on strike Saturday to protest poor working conditions.

Trade unions representing aviation workers at airports said around 80 percent of workers in Lisbon and 50 percent in Faro and Porto airports had gone on strike, according to local media.

TAP airline told passengers to get to Portuguese airports at least four hours before their boarding time due to the strike.

Staff from Prosegur and Securitas, in charge of x-raying hand baggage and controlling passengers began the strike on Friday at midnight following over nine months of negotiations for a new collective work contract.

The airport workers union Sitava told local media that staff at airports were on strike mainly due to unpaid overtime.

Lisbon airport has been especially affected, with passengers suffering a significantly long waiting time for safety checks and flights being delayed up to an hour.

Source : XINHUA