(Adds strike threat, union reaction and Osterloh comments)
BERLIN, Jan 30 (Reuters) - Volkswagen faces strikes in Germany on Thursday after unions rejected an improved pay offer, adding to pressure on the carmaker as it battles to contain a scandal over diesel fume tests.
Europe's largest automaker offered on Tuesday to raise wages for about 120,000 workers at facilities in western Germany by 3.5 percent and a subsequent 2 percent as part of a wage contract proposal covering 30 months.
But the offer was dismissed by Bernd Osterloh, VW's top labour representative and a member of the IG Metall union which is demanding a 6 percent pay rise for 12 months, an improvement in the corporate pension scheme and more hiring of apprentices to help cope with an industry shift to new technologies.
"We will fight for a good pay increase, a decent company pension and socially responsible apprenticeships," Osterloh said. "Volkswagen should be ashamed as to how workers are being treated here given the billions of profits and millions of executive bonuses."
VW pay negotiator Martin Rosik said the offer, which he said included a significant improvement in the company pension plan, would help preserve jobs and the carmaker's ability to invest.
"Volkswagen needs a wage agreement with a sense of proportion," Rosik said after a third round of talks in Hanover. The carmaker's previous pay offer was for a 2 percent increase over 12 months, plus a one-off payment of 200 euros ($249).
Osterloh called on staff to brace for a tough wage round and demanded that workers get a fair share of the profits at VW, which last year increased sales to a record 10.7 million cars.
"We will not tolerate that a company where social responsibility always used to play a major role will be managed from one scandal to the next," Osterloh said, referring to revelations that VW had sponsored tests that exposed monkeys and humans to diesel exhaust fumes.
($1 = 0.8039 euros) (Reporting by Andreas Cremer; Editing by Arno Schuetze and Mark Potter)