SINGAPORE (Reuters) - Singapore Exchange (SGX) has held talks with Saudi Aramco on a secondary listing, two sources familiar with the matter said on Monday, after the oil and gas company suggested last week it would likely simultaneously list on more than one exchange.

The planned listing next year of up to 5 per cent of Aramco is expected to be the world's biggest initial public offer (IPO).

Saudi Energy Minister Khalid al-Falih said last week the company was evaluating concurrent listings on more than one exchange.

The sources told Reuters that the SGX talks were still at an early stage as Saudi Aramco reviews several markets including New York, London, Hong Kong and Japan.

"This transaction is very open and in the public space. The key thing is there is quite a bit of time for due diligence and SGX is keen to play up its international appeal in this sector," said one source.

Aramco, which is slated to list in 2018, could also interest Singapore's sovereign wealth fund GIC, another source told Reuters, but a decision on the size of stake would depend on Aramco's financial details and valuation.

Saudi Aramco and GIC declined comment, while SGX said in a statement that it was the world's most international exchange and "offered unique access to Southeast Asia's markets".

SGX has taken measures to boost market liquidity and attract large IPOs but it has mostly become a large Asian centre for real estate investment trusts (Reits) listings.

In pitching for Aramco, Singapore is playing up its emergence as one of the world's leading oil trading centres, which is also home to 80 per cent of the top 30 oil and gas companies.

Last November, SGX and Japan's TOCOM announced they would join forces in order to co-list Asian LNG and electricity futures.

Singapore has so far been seen to lack a big enough consumer base to warrant a real trading hub, although investors and market participants appreciate Singapore's well established trading regulations, as well as the fact that English is its operating language.