The test runs from 10am-5pm, but Friday's action has been heavily limited due to rain and track time may be extended to compensate.
Four MotoGP and two Moto2 riders are attending the test - being used to gather data, assess the suitability of the facilities and promote MotoGP ahead of the circuit's race debut on the 2014 calendar.
Argentina last hosted a Motorcycle Grand Prix in 1999...
1. Cal Crutchlow
GBR Monster Yamaha Tech 3 (YZR-M1) 1m 57.695s
2. Alvaro Bautista
ESP Go&Fun Honda Gresini (RC213V) 1m 58.000s
3. Stefan Bradl
GER LCR Honda MotoGP (RC213V) 1m 58.266s
4. Hector Barbera
ESP Avintia Blusens (FTR-Kawasaki CRT) 1m 59.971s
5. Nicolas Terol
ESP Mapfre Aspar Team (Suter Moto2) 2m 0.456s
6. Esteve Rabat
ESP Tuenti HP 40 (Pons Kalex Moto2) 2m 8.894s
Fastest Thursday time:
GER LCR Honda MotoGP (RC213V) 1m 44.188s