(Writes through, adds quote from CEO, details)

By Denise Luna

RIO DE JANEIRO, Jan 23 (Reuters) - Brazil's state-run energy company Petrobras announced on Friday it would raise its five-year investment plan by 55 percent at a time when large raw materials companies around the world are cutting back budgets in the face of falling prices and demand.

Petrobras (PETR4.SA: Quote, Profile, Research)(PBR.N: Quote, Profile, Research) said it plans to invest a massive $174.4 billion from 2009 through 2013, compared with the $112.4 billion planned for investment for 2008-12. The company will invest $28.6 billion in 2009 alone.

"It is a very robust investment for Petrobras, for the oil and gas sector and the supply chain, which will have a significant impact on the national economy," Chief Executive Jose Sergio Gabrielli told reporters.

Brazil's promising new subsalt oil reserves that could hold well over 50 billion barrels of light oil and gas will receive $28 billion of the budget over the next five years.

Gabrielli added that he hoped to revise the budget down over time, as the cost of equipment and services in the energy sector are expected to fall with a slowing world economy.

Petrobras had delayed the release of its investment plan four times over the past six months due to the deteriorating global financial crisis. The 2008-2012 plan was announced in August 2007. It plans to hold a second, more detailed conference over its investment plan on Monday.

Gabrielli said the budget-setting process was not typical this time as the board of the company met in Brasilia earlier on Friday where President Luiz Inacio Lula da Silva was present in the final budget discussions for the first time.