* Petrobas undersea pipeline links oilfield to refinery
* Deal worth more than 100 million euros - source
* Voestalpine gives no financial details (Adds quotes and details)
VIENNA, July 7 (Reuters) - Voestalpine has won a contract to deliver 120,000 tonnes of high-strength steel plates for a pipeline Petrobras is building off Brazil at the world's largest oilfield, the Austrian group said on Monday.
It is Voestalpine's second big pipeline deal this year after an accord to supply steel for the South Stream pipeline to bring Russian gas to Europe.
Voestalpine will supply sour-gas-resistant linepipe plates for the Brazilian Rota 3 undersea project between September 2014 and March 2015, it said in a statement that gave no financial details.
A source familiar with the situation said the deal was worth more than 100 million euros ($136 million). Voestalpine had no comment.
Rota 3 is a 380-km pipeline connecting the natural gas and oilfield in the Santos basin just off the coast of Rio de Janeiro with the Comberj refinery, it said.
Voestalpine shares were down 0.7 percent at 34.155 euros by 1011 GMT.
$1 = 0.7331 Euros Reporting by Michael Shields and Angelika Gruber; Editing by Ruth Pitchford