Given developments in the Ukraine and tensions elsewhere in the world, the time has come to put security and geo-political issues directly on the agenda for the meeting of G20 leaders, and for those leaders to bring their foreign ministers to the Brisbane Summit.

Soon after President Bush announced he was inviting G20 leaders to Washington for a meeting in November 2008, there was a phone hook-up by officials to discuss arrangements. The first issue raised was which ministers should accompany leaders to Washington. A number of countries said their foreign ministers should be there. As chair, the US said it was a meeting in response to a financial crisis and only finance ministers should attend.

In the years since, there has been a debate between finance and foreign policy officials as to whether the G20 leaders' agenda should move beyond economic issues. The argument from foreign policy officials was that focusing solely on economic issues was too narrow for leaders in a post-crisis world. Finance officials countered by saying that the legacy of the crisis was still prevalent, the agenda had already expanded too much, and it was better to consolidate the G20 before taking on new issues. As a former finance official, I argued for keeping the G20 focused solely on economic issues.

But when the facts change, you should reconsider your position. And in the light of developments, I now believe the G20 leaders' summit must move beyond economic issues and explicitly discuss security and political matters.

The focus on whether Australia should exclude President Putin from the Brisbane Summit has changed the character of the G20. While it is not up to Australia alone to determine whether Putin should attend a G20 summit, the mere discussion of whether he should come to Brisbane has brought security issues within the ambit of the G20. This is not a new development. The crisis in Syria dominated the St Petersburg Summit in 2013. But with geopolitical tensions rising across many fronts — Ukraine, Syria, Iraq, Gaza, North Korea, the South China Sea — the time has come to put security matters directly on the G20 Leaders' agenda.

In commenting on whether Putin should attend the Brisbane Summit, my colleague Michael Fullilove said he doubted Putin would want to confront a hostile public response at the Brisbane Summit. However, Putin may not show his hand as to whether he is coming to Brisbane until the last minute. Meanwhile, in the lead-up to the summit the Australian Government may be under significant public pressure not to let Putin come. Yet if Australia sought to exclude Putin, this may bring into question the attendance of some other countries. It would certainly be a contentious and distracting issue prior to the Brisbane Summit.

Another colleague, Sam Roggeveen, asked last week: 'if his (Putin) intransigence continues, will Abbott be able to greet Putin with a handshake in Brisbane before the world's media? That will make for an awkward photo-op'.

But there is an alternative approach to handling this matter. If geo-political and security issues were explicitly placed on the leaders' agenda for the Brisbane Summit, the Australian Government's position could be that Putin must come and account for Russia's actions in the Ukraine and elsewhere. In such circumstances, a stern-faced Abbott meeting Putin in Brisbane would make a very different photo-op.

Bruce Jones from Brookings previously suggested that leaders should bring their foreign ministers, national security advisors or relevant diplomats to Brisbane and be available in the event of a crisis which would demand leaders' attention. There are now sufficient geopolitical tensions demanding leaders' attention that security matters should explicitly be on the agenda for the Brisbane Summit. As Jones notes, 'there is no question that a phase of mounting geopolitical tensions has begun'.

Is the G20 the right forum to deal with security and political matters? The UN Security Council has its role, but it also has its limitations. The strength of the G20 is that it is a leader's level meeting and it is more representative than the G7. Moreover, escalating regional tensions are directly related to the performance of the global economy. As Nobel Laureate in economics Michael Spence has noted, 'at this moment in history, the main threats to prosperity — those that urgently need world leaders' attention and effective international cooperation — are the huge uncontained negative spillover effects of regional tensions, conflict, and competing claims to spheres of influence.'

Australia should be proactive. It should signal now that geo-political tensions will be discussed at the Brisbane Summit. But expectations should be managed. There should be no suggestions in advance that major breakthroughs or landmark agreements will be reached in Brisbane. Rather, it should be presented as an opportunity for some frank exchanges between leaders on issues of global importance. Moulding the G20 summit to cover such matters could be the legacy achievement for Australia's turn as G20 president.