Scotland will face the former Eastern European giants on Sunday in Invercargill in their opening pool encounter.
And although Scotland will be expected to win the match with ease - particularly after their warm-up victories over Ireland and Italy - De Luca has warned that the Romanians should not be underestimated.
"I think the main thing to do is get a victory," said the Edinburgh centre. "It's going to be very difficult.
"A lot of boys will be playing their second game and may be rusty unfortunately."
Scotland follow-up the clash against Romania against the new powerhouses of Eastern Europe, Georgia - with De Luca knowing victory in both clashes is vital.
The 27-year-old added: "Both games are very important. They are seen as must-wins and should-be-wins.
"With them being only four days apart there might be a lot of changes.
"There is no indication whether it will be the strongest side or a mixture for both. We are in the dark. You just have to do your best in training and give it a go."
While De Luca is unsure whether he will play the first game, he is adamant that his preferred position is at outside centre.
And he believes he can form a good partnership with Glasgow centre Graeme Morrison if called upon.
"Me and Graeme have only had a handful of games together but we are comfortable in there," De Luca said.
"We have been together for four years and all the players know each other very well.
"We know each other inside out, which is a great bonus."
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