Prime Minister Victor Ponta, whose leftist alliance alarmed the EU last year by attempting to impeach President Traian Băsescu, its main political rival, announced the nominations which he said would ensure "political and judicial stability".
The EU, which Romania joined in 2007, has put its justice system under special monitoring (see background) and asked Bucharest to pick chief prosecutors through a transparent process of applications and interviews, to ensure they were not political appointments.
Ponta, who is also interim justice minister, went back and forth on the nominations. On Tuesday, after meeting the country's Supreme Council of Magistrates (CSM), he said nominations would come only after a transparent and lengthy process.
But on Wednesday he nominated candidates for the general prosecutor's office, the anti-corruption department and the organised crime unit. They must still be confirmed by the president.
"That the prime minister changed his mind again reflects his contempt for the magistrates council and a lack of political coherence," said Laura Stefan, a legal specialist at the Expert Forum think tank.
"The European Commission has clearly required transparency."
Under Romanian law, the president appoints chief prosecutors who have been proposed by the justice minister and received non-binding approval from the CSM, a procedure many analysts consider to be politicised.
Adrian Basaraba, a political science professor at the University of Timisoara, said Ponta's nominations appeared aimed at easing tensions between and within political parties, but were unlikely to achieve that end.
"The nominations are a political compromise that try to mollify everybody," he said.
"But on the one hand they raise tensions in his alliance and on the other they won't necessarily improve the judiciary."
Ponta's nominee to head the anti-corruption unit - former general prosecutor Laura Codruţa Kövesi who was praised by Brussels - was criticised by a faction of his Social Liberal Union (USL), which said Ponta had struck a deal with their opponent Băsescu.
"For the first time since the USL was created, the prime minister ... made a decision without consulting us and with which we fundamentally disagree," said Senate speaker Crin Antonescu, who co-leads the USL with Ponta. He added that the alliance would stick together despite concerns about the decision.