The prosecutors said there was not enough evidence to press charges against former National Security Council secretary-general Chiou I-jen (pictured) and former foreign minister James Huang in the scandal.
They said that Ching Chi-ju, former vice chairman of the Taipei-based BES Engineering and his associate, Wu Shih-tsai, allegedly told Chiou and Huang that they could help broker the establishment of diplomatic relations with PNG, if the government remitted $US29.8 million to a joint bank account set up by them.
The ministry, in a bid to promote diplomatic relations with PNG, remitted the money to the joint bank account. But it turned out to be a fraud, and the two made off with all the money in the account.
Chiou and Huang allegedly were also involved in dividing up the money.
But prosecutors said their investigation showed that Huang had taken a cautious attitude in reviewing the establishment of diplomatic relations with PNG, and if he had wanted to line his pocket, he didn't have to remit money to Singapore.
Prosecutors have not found any evidence that the money in the account in Singapore was channelled into the banking accounts of Chiou and Huang or their family members.