"At the moment, I see as enemies of Spain's recovery the political instability -- it's a possible enemy of the recovery -- and then Greece," Rajoy told a press conference in Madrid.
Rajoy, whose conservatives faces a challenge in local elections in May from the anti-austerity Podemos party, an ally of Greece's ruling Syriza, accused the government in Athens of taking the country down the wrong path.
"Things weren't going badly (in Greece). Then the government changed. The new government decided to say that it accepted none of what the European Commission, the European Central Bank and the International Monetary Fund said.
"But these three are its creditors and if it doesn't accept (their terms) it risks having its funding cut," Rajoy added.
The key, he said, was to have "growth and employment. And for that you have to do like everyone else: fiscal consolidation, structural reforms, etc."
Linking the situation in Greece with that in Spain, which was also battered by the eurozone debt crisis and which is gearing up for a general election expected at the end of the year, he said: "Spain is the first to want things to go well for Greece."
"No-one hates Greece or Mr Varoufakis," Greece's finance minister, he declared.
His remarks came as Greece prepared to resume negotiations Monday on a deal needed to unlock 7.2 billion euros ($7.8 billion) in remaining EU-International Monetary Fund bailout money, according to a Greek government source.
Disillusioned with the ruling conservatives and the opposition Socialists, many voters have been wooed by Podemos and Ciudadanos, another new party that campaigns against corruption but takes a more liberal economic line.
Membership of Ciudadanos -- "Citizens" in English -- has jumped from 2,000 to 20,000 in less than a year.
While Podemos's surge appeared unstoppable earlier this year, a new survey published Monday showed the party bringing up the rear among the four main contenders.
The survey by the Spain-based MyWord Institute showed Rajoy's PP still on top with 22 percent of voting intentions, ahead of the Socialists with 21 percent, Ciudadanos with 19.4 percent and Podemos trailing with 17.9 percent.