NEW Zealand's competition watchdog, which is in the thick of a probe into an alleged cargo price-fixing cartel, has filed criminal charges against three international carriers including Singapore Airlines Cargo, for allegedly withholding information.

The New Zealand Commerce Commission (NZCC) said the charges against SIA Cargo, Cathay Pacific and Aerolineas Argentinas allege non-compliance with notices seeking documents and information that were issued under New Zealand's Commerce Act in October 2007.

The commission is investigating allegations some airlines have colluded to reach agreements and understandings on the level of cargo rates, including fuel surcharges, on international flights to and from New Zealand, chairman Paula Rebstock said in a statement.

SIA Cargo, in response to queries from The Straits Times, denied any wrongdoing. A spokemsan said that the airline will 'vigorously defend' the allegations made, adding: 'SIA Cargo has answered all aspects of the notice relating to its New Zealand based operations. It has also made available officers to assist the NZCC with its investigation and is cooperating'.

'However, the notice sought information on operations outside New Zealand. SIA Cargo believes those aspects of the notice asked more of it than the law requires, and are invalid'.

SIA Cargo had suggested to the commission that both parties should seek a judicial review of the contested part of the notice.

Said the SIA spokesman: 'SIA Cargo is disappointed that the NZCC has chosen this path to resolve the issue, and will defend the matter'. 'SIA Cargo denies any wrongful non-compliance'.

The commission has indicated that it will file proceedings in the High Court later this year. If the airlines are found in breach of section 103 of the Commerce Act, they can be fined up to NZ$30,000 (S$31,202).

Ms Rebstock said: 'Any failure to comply with ... statutory notices that form part of a commission investigation is a serious enforcement issue'.

'Cartels are insidious and cause extensive damage to the New Zealand economy....They are difficult to detect and extremely difficult to investigate because of their secretive nature'.

Apart from the case now pending in New Zealand, authorities in Australia, the United States and in Europe are also investigating alleged air cargo price cartels.

In the US, British Airways, Korean Air, Qantas and Japan Airlines have settled and agreed to pay record fines. US courts have so far awarded penalties of US$1.2 billion (S$1.62 billion) against airlines for participation in an alleged cartel that hiked rates for air cargo coming in and out of the country.