Tabcorp has issued a public apology after a major technical glitch prevented punters from wagering on the final day of the Melbourne Cup carnival.

The issue, believed to have been caused by a disruption to the power at one of their server location centres, shut down the TAB's systems on one of the premier days of the spring.

Racing officials around the country delayed their meetings in the hope the problem would be rectified but it continued into the afternoon and evening with many frustrated punters unable to place bets.

South Australia took the drastic step of postponing the final seven races at Morphettville Parks until Monday.

Corporate bookmakers continued to operate, although many were unable to offer exotics as they rely on TAB dividends.

"Tabcorp wishes to apologise to our customers, the racing industry, venues and other partners for the issues being experienced in the delivery of our products and services today," Tabcorp's managing director and CEO, David Attenborough, said in a statement.

"We appreciate the importance of today's race meetings, especially at Flemington and Rosehill Gardens, and are disappointed that we have been unable to give customers the experience the day deserves."

Tabcorp said its technology teams were continuing to try to restore their services, which were still down as the final races were run at Flemington and Rosehill.