Ruddock joined the troubled region as a consultant at the start of December and is now taking on a permanent position.

Ospreys have lost 13 out of 14 games this season and parted company with head coach Allen Clarke.

Coaches Carl Hogg and Matt Sherratt will continue to take charge of first-team affairs on the training ground as they have since Clarke's departure.

Ospreys are looking to appoint a new head coach while Sherratt is also leaving the region at the end of the season to take up a position at Worcester.

Ospreys have not won since 12 October and have suffered 11 successive Pro14 and Champions Cup losses.

Wales captain Alun Wyn Jones has criticised the Ospreys off-field management and raised questions over recruitment and accountability.

Ruddock was initially brought in from Irish club side Lansdowne to "offer support and advice" to Sherratt and Hogg while reviewing rugby operations with the struggling region.

Ospreys had negotiated Ruddock's release from his current coaching role with Lansdowne FC in Dublin and with Acorn Recruitment.

At the time of his appointment Ruddock said he was unsure whether he would stay with the struggling Pro14 region beyond a month.

The region has since parted company with previous head coach Allen Clarke who had not been in charge of first-team affairs since the end of November with the final departure happening on 30 December.

Ospreys had lost eight out of nine competitive games prior to Ruddock's initial arrival.

They've subsequently lost a further five in a row, including two 40 point defeats against Racing 92 in the Champions Cup and three Welsh Pro14 Christmas Derby losses including a 44-0 hammering at Scarlets on Boxing Day.

After considerable success with Newport Gwent Dragons, Ruddock succeeded Steve Hansen as Wales coach in 2004, winning the Grand Slam at his first attempt in 2005.

After leaving the Wales job in February 2006, he then spent three seasons with Worcester Warriors, from 2007 to 2010, following relegation from the Premiership.

Ruddock was appointed as head coach of the Ireland Under-20s in 2010 before becoming involved with Lansdowne.