VIENNA (Reuters) - U.N. nuclear inspectors hope to gain access to the Parchin military site during a visit to Iran this week as part of an investigation into suspected atom bomb research, the delegation leader said on Tuesday.

The International Atomic Energy Agency (IAEA) aims to finalize a framework deal with Iran in Wednesday's talks in Tehran that would enable it to resume its inquiry, IAEA Deputy Director General Herman Nackaerts said.

He was speaking at Vienna airport before he and a team of other senior IAEA officials departed for the Iranian capital for a new round of negotiations, which have so far failed to achieve a breakthrough.

"We hope that we will be allowed to go to Parchin and if access is granted we will welcome the chance to do so," Nackaerts told reporters. "We are ready to go."

The IAEA, whose mission it is to prevent the spread of nuclear weapons in the world, has been trying for a year to negotiate a so-called structured approach with Tehran that would give it access to sites, officials and documents in Iran.

Both the IAEA and Tehran have said progress was made at their last meeting in the Iranian capital in mid-December, without giving details.

"We are aiming to finalize the structured approach to resolving the outstanding issues on the possible military dimensions of Iran's nuclear program," Nackaerts said.

(Reporting by Fredrik Dahl; Editing by Angus MacSwan)