"We've always been open to discussing anything with Saudi Arabia. Saudi Arabia is our neighbor. We're going to be here together permanently," Press TV quoted Zarif as saying in an interview with Turkey's TRT World.
"We don't have any choice but to talk to each other, and we have been open to talking to Saudi Arabia either directly or through intermediaries," he said.
"We've never rejected any intermediary... We've always been open to mediation, and we've always been open to direct talks with our Saudi neighbours," Zarif added when asked about Khan's visit to Tehran.
Khan will embark on an official visit to Iran and Saudi Arabia as part of Islamabad's efforts to defuse increasing tensions in the Middle East.
Khan would first travel to Iran where he will have a night stay. His meeting with President Hassan Rouhani has been scheduled for Sunday. He will later in the day go to Riyadh for meetings with the Saudi leadership, according to Pakistan's Dawn news.
In his interview with TRT, Zarif emphasized that Saudi Arabia needs to start good relations with its neighbors if it wants to be secure.
"Buying weapons will not buy you security. If Saudi Arabia wants to be secure, the best way is to end the war in Yemen, to start good relations with its neighbours and the neighbourhood, and not to trust the US," Press TV quoted Zarif as saying in the TRT World interview.
He also referred to a peace plan, officially called Hormuz Peace Endeavour (HOPE), proposed by Rouhani during his recent speech at the annual meeting of the UN General Assembly (UNGA), saying the initiative calls on "all eight countries in the Persian Gulf region to join in an attempt to bring peace through dialogue".
"We hope it can be discussed and further enriched by our neighbours," he added.
The mediation initiative is being taken at the request of Saudi Arabia. Crown Prince Mohammad bin Salman had during Khan's last visit to Saudi Arabia asked him to help defuse tensions with Iran as Riyadh wanted to avoid war.
Tensions have been brewing between Tehran and Riyadh since the September 14 drone attacks on a Saudi oil facility and a processing plant.
Although the Yemeni Houthi rebels have claimed responsibility, both Saudi Arabia and the US have blamed Iran for the drone strikes - a charge Tehran has strongly rebutted.
On the sidelines of the UNGA session in New York last month, Khan met Rouhani as part of the diplomatic push to defuse the Middle East tensions.