UN Secretary-General Ban Ki-moon said on Sunday that he had invited Iran to attend this week's Syria peace conference in Switzerland, also known as Geneva II.

"I have decided to issue some additional invitations to the one-day gathering in Montreux. They are: Australia, Bahrain, Belgium, Greece, the Holy See, Luxembourg, Mexico, the Netherlands, the Republic of Korea, and Iran," Ban told reporters at a press conference.

"I believe the expanded international presence on that day will be an important and useful show of solidarity in advance of the hard work that the Syrian government and opposition delegations will begin two days later in Geneva," he said.

The UN chief will depart for Montreux on Monday to chair the event, which will be held in two parts. Following its opening session in Montreux on Jan. 22, it will then move on Jan. 24 to the Palais des Nations in Geneva where Lakhdar Brahimi, the United Nations and Arab League Joint Special Representative for Syria, will facilitate the talks between the two Syrian parties.

Recent regional and international talks have focused on whether Iran will participate in the upcoming Geneva II peace conference or not, following attempts by Western powers to curb the Islamic republic's participation.

Iran said it would take part in the conference if it is invited without preconditions set by the West. The Persian country has been a main backer of the Syrian government during Syria's long- standing conflict.

"I believe strongly that Iran needs to be part of the solution to the Syrian crisis," Ban said at the press conference.

The UN secretary-general noted that he made the invitation after he had spoken "at length in recent days with Iran's Foreign Minister" Mohammad Javad Zarif.

"He has assured me that, like all the other countries invited to the opening day discussions in Montreux, Iran understands that the basis of the talks is the full implementation of the 30 June 2012 Geneva Communique," Ban said.

"Foreign Minister Zarif and I agree that the goal of the negotiations is to establish, by mutual consent, a transitional governing body with full executive powers," he said. "It was on that basis that Foreign Minister Zarif pledged that Iran would play a positive and constructive role in Montreux."

"Therefore, as convener and host of the conference, I have decided to issue an invitation to Iran to participate," said the UN chief.

Ban went on to call on "all those who come to Montreux to act in good faith," but noting that "Montreux is not a venue for negotiations."

"The Syrian parties themselves will begin that process in Geneva on 24 January," he said. "I especially appeal to the Syrian parties themselves to keep one goal in mind: the end of the suffering of the Syrian people and the beginning of a transition to a new Syria."

At the press conference, the UN secretary-general also welcomed the decision by the National Coalition of Syrian Revolution and Armed Forces, Syria's main opposition bloc, to participate the Geneva II peace talks.

"I look forward to seeing an inclusive opposition delegation," he added.