Petrobras notified Ensco saying that the contract was void, according to the US Securities and Exchange Commission filing by Ensco.

Petrobras claims that it chartered the DS-5 drill ship in 2008 when it was owned by Pride International.

However, in 2011 Pride International was acquired by Ensco.

Petrobras’ notice highlighted that Pride knew that the rig’s shipbuilder made "improper payments" to a marketing consultant and had the money from the deal divided amongst former employees of Petrobras, Ensco said.

Ensco however said: "Without specifying any supporting facts or conduct, Petrobras’ notice alleges that Pride had knowledge that the shipbuilder of DS-5 made improper payments to the former third-party marketing consultant who then shared the improper payments with former employees of Petrobras and that Pride may have assisted in or facilitated these improper payments.

"Contrary to Petrobras’ assertion, the Company has found no evidence that any current or former employee of Pride or Ensco was involved in any wrongdoing, had knowledge of any wrongdoing, or authorized the former third-party marketing consultant to engage in any wrongdoing on behalf of Pride or Ensco with respect to the shipbuilding contract for DS-5.

The company said it has not been contracted by Brazilian authorities in this regard and it will take legal recourse. Petrobras has been trying to cut back spending and sell assets to recover from a scandal that made the company to write off $2.1bn in corruption losses.

Ensco has provided other rigs to Petrobras including ENSCO 6001, 6002, 6003 and 6004 which will continue to operate as per the contracts.