World champion Lewis Hamilton recovered from an early spin during the morning session on day three of Formula 1's second pre-season test in Barcelona, where Ferrari driver Charles Leclerc set the fastest time.

Hamilton's Mercedes was called back to the pits following nine laps on Thursday after spinning at Turn 10.

The British driver, though, was soon on course again, running C2 tyres, to set the second fastest time of the morning before moving clear at the top of the board after a lap of one minute and 18.097 seconds.

Red Bull's Pierre Gasly swiftly lowered the mark at 1min 17.91secs on medium compound C3 tyres.

McLaren rookie Lando Norris also impressed as the 19-year-old twice set another fastest time, moving clear again of Toro Rosso's Alex Albon at 1:17.084.

As the session continued towards the lunch break, Albon laid down another marker at 1:16.882.

However, it was Scuderia driver Leclerc who made an impressive late charge on C5 Pirelli tyres to continue to drop the time, finishing clear on 1:16.231.

Hamilton completed some 85 laps, ending on C3 medium tyres, and was in eighth overall, with Norris third.

Ferrari, meanwhile, moved to confirm the cause of Sebastian Vettel's crash during Wednesday.

The four-time world champion was taken to the medical centre and declared unhurt by his team after he went straight on at turn three and ploughed into the barriers due to a front-end mechanical problem.

Vettel had already registered the third fastest time during his 40 laps on Wednesday morning.

"After thorough checks we found that Seb's off yesterday was due to a (wheel) rim issue," a statement from a Ferrari spokesperson read.

"The rim had been damaged a few seconds before by an impact with a foreign object."

German Vettel is not expected to drive on Thursday, with Leclerc in the hotseat for both sessions.

Friday will be the last of the eight days of pre-season testing.

The opening round of the 2019 world championship is scheduled to start in Melbourne on March 17.