Perth-based internet service provider iiNet has posted a 122 per cent jump in first-half profit to $32 million following two significant acquisitions.

The result was achieved on revenue of $474 million, up 30 per cent on the previous corresponding period.

Operating cash flow was up 204 per cent to $72 million and the company reduced its debt to equity ratio to 66 per cent.

The company lifted its interim dividend by 33 per cent to eight cents a share, fully franked.

iiNet attributed the stronger result to the acquisition of Internode and TransACT last year but also noted its margins had improved.

iiNet's managing director and chief executive Michael Malone said the company's strong cash flows had enabled it to pursue attractive strategic acquisitions, quickly pay down debt and grow dividends.

"iiNet's recent entry into the S&P/ASX200 Index is a milestone we are all very proud of," he said.

"We are in the best position we have ever been in the company's 20-year history."