(Adds comments from companies cited by the comptroller)
RIO DE JANEIRO, March 11 (Reuters) - Brazil's office of the comptroller general said on Wednesday it had opened a case against 10 additional firms that may be involved in a massive corruption scheme at state-run oil firm Petroleo Brasileiro SA .
The case runs against Alumini Engenharia, GDK, Promon Engenharia, Andrade Gutierrez, Fidens Engenharia, Sanko-Sider, Odebrecht, Odebrecht Óleo e Gás, Odebrecht Ambiental and SOG Óleo e Gás, according to a statement from the comptroller general, known as the CGU.
The process may prevent the companies, which include some of Brazil's biggest builders, from signing new contracts and lead to fines and other penalties, the comptroller said.
In December, the CGU opened a case against eight construction companies that had ties with Petrobras, leaving many of them in financial trouble as they lost revenue and access to capital markets.
Brazil's biggest-ever corruption scandal is rippling through various sectors of Brazil's economy. Large infrastructure projects will likely be stalled with so many engineering firms under investigation.
Contacted by Reuters, Andrade Gutierrez said "it has never been involved in any of the facts currently being investigated."
Builder Odebrecht said it has never taken part in any cartel and that it won all its contracts with Petrobras in accordance to the legislation.
Odebrecht Ambiental, which specializes in water and sewage services, said it sees no reason to be on the CGU's list as its work is not related to the activities currently being investigated.
Drilling firm Odebrecht Óleo e Gás vehemently denied its participation in any wrongdoing and reaffirmed that all its Petrobras contracts were obtained in accordance to the Brazilian legislation.
Alumini Engenharia representatives said the company vehemently disputes the accusations and has always guided its business with ethical and transparent standards.
Fidens Engenharia said it will prove that it has not taken part in any irregularity.
Sanko-Sider, an importer of pipes, said it sees no reason for being on the CGU list as it never sold its products to Petrobras nor participated in bidding processes involving public money.
Representatives for Promon Engenharia and GDK said the companies could only comment after being officially notified by the CGU.
Reuters was not able to reach representatives for SOG Óleo e Gás.
In the first phase of a year-old corruption and money laundering probe, executives from six engineering firms were charged with forming a cartel that funneled funds from Petrobras contracts to politicians and political parties. (Reporting by Walter Brandimarte and Marta Nogueira; Editing by Chizu Nomiyama, Meredith Mazzilli and Chris Reese)