March 19 (Reuters) - Australia's competition regulator said on Thursday that it has launched an investigation into allegations of anti-competitive conduct by major fuel suppliers, including Ampol ( CTXAF ), BP's Australian unit, Mobil Oil Australia and Viva Energy's ( VVEGF ) unit.

The Australian Competition and Consumer Commission (ACCC) said it received reports regarding diesel availability to independent wholesalers and distributors serving regional and rural areas, and would assess the alleged conduct.

The investigation comes amid widespread concerns from consumers, businesses, and farmers over fuel prices and supply, heightened by the Middle Eastern conflict.

Ampol ( CTXAF ) and Viva Energy ( VVEGF ) did not immediately respond to Reuters requests for comment.

A spokesperson for ExxonMobil Australia said the firm has been "working cooperatively with the Federal Government," and will continue to work to meet their obligations to customers "to provide the fuel that Australia needs".

A spokesperson for BP Australia said the company "acknowledges the ACCC's investigation into its market practices," adding that it takes "these matters seriously and are reviewing the claims raised."

The ACCC said the investigation is at a preliminary stage and that it has not yet reached any conclusions on the matters.

"It is not our usual practice to publicly announce investigations, but given the significance of the issue, the ACCC is confirming this investigation," said ACCC Chair Gina Cass-Gottlieb.

The competition regulator added it is closely monitoring fuel markets and will act, if needed, to enforce competition and consumer laws.