A unit of MCI WorldCom will make a cash offer for the complete acquisition of OzEmail in a deal expected to challenge the Australian Internet service provider's most significant competitor, Telstra. The US-based telco giant yesterday announced its wholly-owned subsidiary UUNET Holdings Australia will offer to buy all the issued ordinary shares of OzEmail for $3.55 a share. OzEmail spokesperson Michael Ward told said the company expected the move, indicating it strengthens MCI WorldCom's existing entry into the local telecommunications market. "MCI wants to make a substantial foray into this market and they see this as an important step," he said. "The directors have indicated it is a reasonable offer."