Russian police have arrested at least 29 opposition protesters in central Moscow for "breaching public order", according to local authorities, a week after hundreds were detained during an anti-corruption rally demanding the prime minister's resignation.

Russia's Interfax news agency said the turnout for Sunday's protest was considerably smaller than last week's event, with only 100 people in attendance.

Before the demonstration, access to several websites promoting what the government said was "an illegal anti-government protest" had been blocked.

The Russian constitution allows public gatherings but recent laws have criminalised protests not authorised by city authorities, which frequently refuse to grant permission for rallies by Kremlin critics.

The organisers of Sunday's rally denied having links with opposition leader Alexei Navalny, who is serving a 15-day jail sentence for his role in organising the March 26 protests, saying it was planned by "young people and ordinary students from Moscow".

Navalny, a Kremlin critic and anti-corruption campaigner, organised last week's protests after publishing a detailed report accusing Russian Prime Minister Dmitry Medvedev of controlling a property empire through a shadowy network of non-profit organisations.

Medvedev, who has so far made no comments on the claims, is accused of amassing a private collection of mansions, yachts and vineyards.