The campaign to replace outgoing President Vladimir Putin began officially with the formal announcement of the March 2 election date in the state newspaper, Rossiiskaya Gazeta.
So far only about a dozen figures with marginal public support have launched a bid, leaving the country waiting for Mr Putin to name his preferred successor - and to explain whether he will really leave power.
Mr Putin, who is not allowed to seek a third consecutive term next year, hopes to see his United Russia party score a massive victory in parliamentary elections.
As controversy grew over the fairness of the polls, aides to Mr Kasparov, arrested during a banned opposition rally in Moscow last Saturday, complained he had been barred access to lawyers and visitors.
"I've tried twice to see my client but I've not been authorised to do that. The officials at the Moscow city police headquarters never explained why and this contradicts all norms of international law," lawyer Olga Mikhailova said.
Kasparov aide Marina Litvinovich says that officially the opposition leader is being held at 38 Petrovka, the address of Moscow city police headquarters.
"However, no one can confirm this because they won't let anyone in to see him," she said.
Also barred from visiting Mr Kasparov are parliament member Vladimir Ryzhkov and Mr Kasparov's longtime bitter chess rival Anatoly Karpov, who is a member of a state-backed civil watchdog. Both men have the right under Russian law to make prison visits.
A city police spokesman told AFP he could not comment.
Mr Kasparov, considered by many the greatest chess player in history and now a bitter opponent of Mr Putin, was arrested while leading an unauthorised protest march and sentenced to five days jail.
The following day some 200 activists were arrested at a similar rally in Saint Petersburg.
US President George W Bush said he was "deeply concerned" by the crackdown.
With Mr Putin still silent on his future plans, Russians are in the dark over who will run the country next year.
Mr Putin says success in the legislative polls will give him a "moral" right to retain an important, but still undefined role, leading many analysts to speculate that the secretive Kremlin leader will not entirely leave power.
The possible Putin successors mentioned most frequently in Russian media are First Deputy Prime Ministers Sergei Ivanov and Dmitry Medvedev, as well as Prime Minister Viktor Zubkov.
The only political figures who have declared their candidacy for the elections so far are from Russia's fractured opposition and include a former prime minister Mikhail Kasyanov and a Soviet-era dissident. © 2007 Australian Broadcasting Corporation