The company says its finance arm may issue the notes subject to market conditions.

If successful, Ausdrill will repay outstanding debt under its $A550 million syndicated bank facility, which was only entered into earlier this month.

The company’s new debt arrangement will enable it to refinance its existing $150 million revolver, refinance about $30 million of asset finance facilities and provide funding for the $165 million acquisition of Best Tractor Parts.

On repayment, $US250 million of the commitments under the facility will be cancelled.

Meanwhile, Ausdrill has been issued ratings by Moody’s Investor Services and Standard & Poor’s.

Moody's assigned a first-time Ba2 corporate family rating to Ausdrill, as well as a provisional Ba3 senior unsecured rating to the proposed $300 million note issue, with a stable outlook on both.

"Ausdrill's corporate family rating reflects its strong market position in relation to the provision of integrated mining services in its target markets and its ability to execute contracts to a diversified range of counterparties," Moody’s vice president and senior analyst Arnon Musiker said.

"However, Ausdrill's rating is challenged by its exposure to countries in Africa with less stable political and operating environment, including Mali.

“The corporate family rating also recognises that Ausdrill has a strong financial profile for pursuing its growth plan, consistent with its track record.

"The rating further reflects our view that the earnings from Ausdrill's Australian operations are subject to cyclicality, with relatively large contributions from equipment hire and mining of iron ore and coal."

Meanwhile, S&P assigned a BB issuer credit rating to Ausdrill with a stable outlook, saying it reflected a weak business risk profile and intermediate financial risk profile.