Sebastian Vettel top in Austria practice, Lewis Hamilton fifth

Ferrari's Sebastian Vettel set the pace in second practice at the Austrian Grand Prix as Lewis Hamilton was fifth after an error-strewn session.

Vettel was 0.011 seconds quicker than Hamilton's Mercedes team-mate Nico Rosberg, with the second Ferrari of Kimi Raikkonen third.

Hamilton failed to complete a lap on his qualifying run on the faster tyres as he made three separate mistakes.

The world champion was behind Lotus's Pastor Maldonado.

Hamilton did not string a good lap together on the faster of the two tyre choices, but was on target to beat Rosberg's time on one lap before running wide at the difficult final corner, Turn Nine.

He had also made errors on two other attempts at a qualifying simulation.

But Hamilton - who leads Rosberg by 17 points in the drivers' title ahead of Sunday's race at 13:00 BST- did set the pace on the first runs of the session, which takes place on the slower of the two tyres.

Then, Hamilton was 0.161secs quicker than Raikkonen and Vettel, who set identical times, with Rosberg fourth, 0.203secs slower than Hamilton.

The race looks set to be a fight between the Mercedes and Ferrari, with the Mercedes-engined Williams, Lotus and Force India teams next up.

But Red Bull are expecting a difficult weekend on a track they own.

Daniil Kvyat and Daniel Ricciardo were 12th and 17th fastest, with a 10-place grid penalty already confirmed for the Australian because of engine changes. Kvyat may also have to take a penalty for the same reason, although the team have yet to confirm this.

Force India's Nico Hulkenberg was sixth ahead of Lotus's Romain Grosjean, the Toro Rosso of Max Verstappen, Felipe Nasr's Sauber and Hulkenberg's team-mate Sergio Perez.

Williams had a low-key day with Valtteri Bottas and Felipe Massa ending up 14th and 15th, but often run heavy on fuel on Friday, disguising their true competitiveness.

McLaren-Honda's problems continued as Jenson Button was forced to abandon running with a loss of power less than halfway through the session.

This had a knock-on effect on team-mate Fernando Alonso as the team stopped him running to prevent similar damage to his engine.

Carlos Sainz Jr's near-miss with the barrier provided the main drama in the afternoon running

The problem raises the possibility of further problems for Alonso, who has already been hit with a 20-place grid this weekend penalty for using too many engine parts so far this season.

But the Spaniard did manage to put some miles on the team's new aerodynamic upgrade, which features a shorter nose and revised front and rear wings.

The team had a scare when governing body the FIA said they could not run the new parts as they had passed the mandatory crash test when attached to a different, lighter monocoque.

McLaren eventually managed to convince the FIA with the help of structural analysis information that the two chassis would behave in the same way in the event of an accident.

Alonso was able to do a handful of laps with the new parts but could manage only 16th fastest time, 1.917secs off the pace.

The new parts are not available to Button, who was 19th, because there is only one set. The 2009 world champion may yet also receive a grid penalty, for the second consecutive race in his case.

Vettel also suffered problems - a gearbox sensor issue meant he was consigned to the garage after setting his fastest time and missed out on doing his race preparation homework.

The German had a difficult day, also missing most of the morning session with an engine problem which stranded him on track after just four laps.

Second practice results

Austrian GP coverage details

Lotus driver Pastor Maldonado was fourth fastest during a promising first day for the team

Lewis Hamilton was half a second off Sebastian Vettel's time in second practice