Athens, Greece: Public transport services and flights by domestic carrier Olympic Airlines are likely to be disrupted Thursday as part of union protests timed coincide with the May 1 Labor Day public holiday.

Transport organizations said Wednesday that public bus services in Athens - including buses to Athens International Airport - would be halted Thursday, while the capital's metro system would only work between 9:00 a.m. and 7:00 p.m. (0600 and 1600GMT).

About half of Olympic Airlines' flights, both international and domestic, will be canceled. Ferry services to Greek islands will probably be disrupted, as well.

Strikers will join rallies in Athens, starting at midday Thursday.

Labor unions are at odds with Greece's conservative government over planned pension reforms which they argue will reduce benefits for most pensioners.

The government says its must merge pension funds and cut early retirement benefits to safeguard the system from collapse in future decades because of the demands of Greece's aging population.