ABN Amro Bank of The Netherlands and the Development Bank of Singapore are apparently enjoying a head start against their foreign rivals because they have made a big gamble by buying out the local Thai banks ahead of a semi-nationalisation of the banking system, banking officials and analysts said.

''The other foreign banks, who have delayed their decision to acquire the Thai banks earlier, may miss the train now that the government has put out a sweeping banking-reform package,'' said Dr Pisit Lee-ahtam, the deputy finance minister.

Vichai Punphocha, general manager of Dresdner Bank BIBF, added that there were no more cheap banks for acquisition because the government had come up with an innovative scheme to nationalise the banking system in a very subtle way. ''It is not an ugly nationalisation, although in essence it is a nationalisation, because the government will be coming up with Bt300 billion to bail out the system and participate in the recapitalisation of the banks. Foreign banks which are late-comers to the scene will not get a deal such as ABN Amro has got with the Bank of Asia,'' he said.

ABN Amro Bank has purchased a 75-per-cent stake in the Bank of Asia, agreeing to pay Bt5 a share and pumping Bt7.5 billion into the Thai bank. ''The foreign banks are indeed interested in the Thai banking industry. As soon as ABN Amro acquired the Bank of Asia, it ordered the Thai banks to increase its ATM network to 200 units,'' said a senior Bank of Thailand official.

Last year Bank of Asia had only 35 ATMs, which quickly jumped to 158 by June 1998 after the arrival of ABN Amro Bank. By the end of this year, it plans to have 200 ATMs, apparently aiming to head off Citibank NA of the US, which is one of the world's most formidable players in retail banking.

''Since ABN Amro Bank has bought the Thai bank at Bt5 a share, it now, with protection from the banking system through the reform package, can only stand to gain,'' said a banking analyst.

Development Bank of Singapore has acquired 51 per cent in Thai Danu Bank, while Bank of Nova Scotia is understood to be in talks to buy 80 per cent in the Nakornthon Bank in a deal carved out right before the introduction of the banking reform package last week. However, with the banking-reform package, the Wanglee family, which controls the Nakornthon Bank, may have more bargaining power to negotiate with Nova Scotia.

Through the acquisitions, ABN Amro Bank is now operating out of 111 nationwide retail branches of Bank of Asia, compared to 96 branches of Thai Danu Bank for the Development Bank of Singapore.

There has been talk that Standard Chartered Bank of the UK is interested in Radhanasin Bank, which last week stepped in to take over Laem Thong Bank through a directive of the banking regulators. If Standard Chartered succeeds in cutting a deal with Radhanasin, it will stand to benefit immediately from Laem Thong's 50 branches without losing time making new investments and recruiting new people.

Other foreign banks which aim to break into the Thai banking industry will now face a tougher job and probably have to dig deeper into their pockets because of their initial delay in cutting the deals. For now the Thai shareholders of the remaining banks will have greater bargaining power because they can resort to government finance to help them recapitalise. The government will have a larger say in determining the course of the remaining banks which will participate in its bail-out programme.

''A requirement for the Thai banks to book full provisionings up front and raise fresh capital in tier 1, matched by a one-to-one government-capital contribution means that the bargaining power has tipped to the Thai side,'' said Vichai.

Earlier the Thai shareholders virtually had no bargaining power, because the rising non-performing loans amid the sharp economic contraction meant that they had to sell cheap otherwise their stocks could be written down to one satang. The foreign banks also expected to buy the Thai banks cheap, thinking that eventually the insolvent banking system would force the Thai government to force the Thai banks to write down their capital and turn them over to foreigners.

The banking-reform package immediately tipped the balance, giving the Thai shareholders more leeway or helping them buy time as they struggled to resolve their NPLs and recapitalise. When he heard about comments that the Thai banks were no longer cheap for foreign banks, Finance Minister Tarrin Nimmanahaeminda said with some satisfaction: ''Good: we never wanted to sell the banks cheap.''

Chaktip Nitibhon, general manager of Credit Agricole Indosuez, said the key obstacles to foreign banks' take-over of Thai banks was the sharp differential between the bid and offer prices and the management structure following the acquisitions. He cautioned that it might be too early to say whether late-comers to the Thai banking industry might not be able to get a bargain since it depended on the future level of the NPLs, the implementation of the package, the liquidity problems and the willingness of Thai banks to extend credit.