South Korea is bracing to step up its military expenditure in case incoming US president Donald Trump reduces the budget for the Korean peninsula. A top South Korean lawmaker has said Seoul would be forced to accept an increasing share of the burden in hosting American troops in the region.

Chang Myoung-jin, minister of the Defence Acquisition Programme Administration (Dapa), has cautioned the South Korean government should be prepared to deal with any policy surprises thrown by Trump once he takes office. Chang added the government needs to cut corners in other areas including welfare measures and hold talks with opposition party members if it has to suddenly increase its military expenditure.

"My basic thought about that is just that if, and this may be a big if, President-elect Trump and his administration, when it comes to the alliance with ROK [Republic of Korea], of course the campaign's rhetoric has been toward that direction, and if there is a huge demand for more burden on the part of the ROK, I think Korea will inevitably have to embrace that," said Chang while speaking at the Centre for Strategic and International Studies in Washington.

During the election campaign, Trump threatened to withdraw American forces from South Korea unless Seoul agrees to bear increased financial burden. Throughout the campaign, he repeatedly asked other US allies such as members of Nato to boost their expenditure if they expect continued support from Washington.

"The current weapons system that we already have in place will have to be maintained continuously and, on top of that, whatever that is lacking in our current weapons system will have to be complemented and enhanced, and whatever has been ageing will have to be replaced," said Chang. He estimated that 10% of next year's budget or about $40bn (£32bn) would be earmarked for defence.

"To have a lot of defence budget secured will be all good. However, it will mean that we will have to cut back on other budgets, which will inevitably invite a lot of resistance. If that ever happens, the ROK government will place ourselves in a dilemma, but our focus and priority will have to be putting first priority on defence."

Dapa has issued a statement clarifying Chang's remarks are only presumptive.