At the same time, King Salman of Saudi Arabia was winding up a 12-day visit to Indonesia with a 1000-man delegation.

Indonesia's regional significance is beyond doubt. Yet it wasn't until the 1990s that we began a consistent approach to recognise the essential importance of our neighbour, the world's most populous Muslim nation.

While the visit of King Salman is the first of a Saudi ruler since 1970, they have been steadily building influence there since the 1980s, funding the construction of many new mosques promoting their illiberal "Wahhabi" strain of Sunni Islam.

King Salman is poised to increase Saudi influence in Indonesia exponentially. In one swoop Saudi investment in Indonesia has gone from $US900,000 last year to $US7 billion, with the Indonesia media reporting that another $US25 billion may be waiting in the wings.

While the Saudis prepare to unload billions, our fiscal investment in our nearest neighbour hovers around $605 million in foreign aid, and Indonesia is not yet one of Australia's top 10 trading partners.

Indonesia's Kompas newspaper reported that King Salman stressed the need for "Muslims and Muslim-majority countries to unite, to face extremism and terrorism as well as the clash between civilisations", and yet they, a corrupt feudal aristocracy, have been promoting that very extremism.

The problem for Indonesia is that while most of its people are Sunni Muslims, known for moderation and basic equality of men and women, Saudi influence since 1980 has been consolidating its much stricter interpretation of the faith, also known as Salafism.

While Saudi Arabia has long funded educational grants to Indonesian students, currently there is only one Saudi-funded tertiary institution in Jakarta, the Islamic and Arabic College of Indonesia (LIPIA). Funding is now offered for three more at Makassar in Sulawesi, Medan in Sumatra and Surabaya in East Java. Students who enrol pay no fees and are given a stipend.

The Jakarta Post has reported that the campus in Jakarta is already known to produce students ingrained "with the conservative strain of Islam, including convicted terrorist Aman Abdurrahman, who has been known for his efforts to spread Islamic State (IS) movement propaganda".

The practice of separating men and women in the context of studying at university means the same lecture is repeated in a completely different room. Singing, music and television are all on the no-go list. Wayang (puppet-theatre) and the accompanying gamelan orchestra which have long been part of traditional Javanese culture are regarded by Wahhabis as anti-Koran.

Indonesian President Joko Widodo acknowledged the Saudi visit as an opportunity for Indonesia to increase trade and benefit from the construction of infrastructure.

As for matters of religion, the Indonesian Minister of Religion, Lukman Hakim Saifuddin, in answering questions from some Jakarta journalists, deflected concern that increased Wahhabi influence would lead to greater radicalisation within Indonesia.

Having to deal with fundamentalist Islamic groups and their financial backers, and at the same time deal with an opposition who seem to be using the state's relationship with Islam as a venue to beat their own political drum, is placing President Jokowi and the entire nation on the horns of a dilemma.

During the Jakarta demonstrations on the eve of the mayoral elections, there was a classic example of how Javanese culture handles contradictions.

It was a Saturday afternoon and a large crowd of demonstrators had gathered around the Istiqlal (Arabic for "independence") mosque. The mosque, partly designed and built by President Sukarno, is adjacent to Indonesia's largest Catholic cathedral, constructed in Dutch times. The crowd was so large it was blocking access for a Batak couple from Sumatra who were to be married in the cathedral.

When the demonstrators realised it was a wedding, they made a path for the car to drive through. All went well and the husband later wrote a thank you note, showing his appreciation for the help given by the demonstrators.

For Indonesia, Saudi investment is constructive, but if the strings attached unleash Wahhabi radicalism to challenge moderate Muslims - and by extension the very fabric of Indonesian society - Australia urgently needs to step up its bilateral ties.

Greg Poulgrain from University Sunshine Coast has just returned from Jakarta.

David Margan, a former media correspondent, is now involved in media consultancy