But discussions scheduled for Thursday in Iran will be overshadowed by Tehran's plan to raise enrichment to an industrial scale.
The visit by ElBaradei, the head of International Atomic Energy Agency (IAEA), comes less than 48 hours after Iran declared that it had enriched uranium to a level used in nuclear power stations and would press ahead with large-scale production.
Tuesday's announcement by Mahmoud Ahmadinejad, the Iranian president, drew stinging rebukes from world powers, including Russia and China, while the United States said the UN Security Council, which could impose sanctions, must take "strong steps".
Iran says it will not back down from what it calls its national right to enrich fuel for civilian purposes and denies accusations by Western nations that it wants atomic bombs.
"It's wishful thinking to think Iran would shut down the nuclear process entirely now," a diplomat at the IAEA said in Vienna.
Iran has enriched uranium to
be used in nuclear power stations
The IAEA chief is expected to meet top Iranian officials, but the diplomat said he was not expected to broker a deal.
The unnamed diplomat said: "They have obviously achieved a significant advance at the research and development level and want to present it as a fait accompli to strengthen their bargaining position with the West."
Iranian analysts echoed that view, saying Iran's nuclear enrichment capability could strengthen the country's hand.
Amir Mohebian, a conservative political analyst, said: "The (language) in negotiation with Mr ElBaradei is now very different from the past, before reaching this ability."
Three European powers - Britain, France and Germany - had been in talks with Iran on suspending its enrichment work but called them off in January after Tehran said it would resume enrichment.
"The (language) in negotiation with Mr ElBaradei is now very different from the past, before reaching this ability"
Conservative political analyst
The Security Council has told Iran to halt all sensitive atomic activities and on March 29 it asked the IAEA to report on its compliance in 30 days, prompting ElBaradei's one-day visit.
ElBaradei said: "I am hopeful that the time is right for a political solution through negotiations. I hope conditions will be created for all parties to return to talks."
Diplomats at the Security Council said the five permanent council members plus Germany would meet in Moscow next week alongside a Group of Eight meeting to discuss Iran.
The diplomats said the council was unlikely to take any substantive action until ElBaradei had made his report at the end of April.