Barnett, 23, scored 14 tries in 20 appearances for Hull after joining them from Gateshead last season but has played only once this year.

The Vikings have already signed St Helens centre Gray Viane for the rest of the season and Warrington scrum-half Jamie Durbin on a month's loan.

"We are delighted to have signed a player as promising as Richie Barnett," said Widnes coach Frank Endacott.