Athens (AFP) - The Greek-flagged tanker Bouboulina, suspected of spilling oil along Brazil's northeastern coast, is ready to hand over the documents requested by Brazilian authorities, a public relations group said Thursday.

The group hired by Bouboulina's owners, Delta Tankers, said Brazilian officials had written to the Greek merchant marine regulator requesting that four shipping companies provide navigation documents as Rio tries to identify the source of spills that began appearing along Brazil's Atlantic coast in early September.

"They will willingly share this documentation with the Greek Ministry of Maritime Affairs and the Brazilian Navy," the communications group said in a statement.

The Bouboulina has been singled out as the "prime suspect" by Brazilian authorities who have studied satellite images of the spill and checked on 1,100 ships that were in the area at the time.

The other tankers concerned were identified by the public relations firm as the Maran Apollo, the Maran Libra, the Minerva Alexandra and the Cap Pembroke.

A source close to the matter said their owners had until November 13 to submit the documents to the Greek ministry.

Oil slicks have tarred more than 200 beaches along a 2,000-kilometre (1,250- mile) stretch of Brazil's most celebrated shoreline.

Delta Tankers has already denied that the Bouboulina was to blame, saying in a statement that "there is no proof of the vessel having stopped, conducted any kind of STS operation (Ship to Ship), leaked, slowed down or veered off course, on its passage from Venezuela to Melaka, Malaysia."

It left Venezuela on July 19 and arrived in Malaysia on September 4.

The communications group said Thursday that Delta Tankers had "conducted a full search of the material from the cameras, data and records," and maintained that the tanker arrived directly in Malaysia where "she discharged her entire cargo without any shortage."

According to Brazilian officials, satellite images put the initial oil spill on July 29, more than 700 kilometres from the Brazilian state of Paraiba.

They were unable to determine however if it had been an accident or was criminal in nature.

President Jair Bolsonaro warned Sunday that "the worst is yet to come," saying only a fraction of the spilled crude had been collected so far.