Inter sign striker Lukaku from Man United

Romelu Lukaku has left Manchester United for Italian side Inter Milan.
Romelu Lukaku has left Manchester United for Italian side Inter Milan.

Romelu Lukaku has completed his big-money switch to Italian giants Inter Milan after weeks of pushing for a Manchester United exit.

It is just two years since the Belgium striker turned down a move to Antonio Conte's Chelsea to leave Everton for Old Trafford in a deal worth an initial STG 75million.

But Lukaku's desire to leave United for pastures new has been clear and Inter, where Conte is now head coach, finally completed a deal for the wantaway forward hours before the English Premier League transfer window closed on Thursday.

The Serie A side saw a 60m euros ($A99 m) offer rebuffed last month and redoubled their efforts after Paulo Dybala's prohibitive demands thwarted a potential swap deal involving Lukaku between United and Juventus.

It is understood Inter will pay up to 80m euros for Lukaku and a sell-on clause has been inserted in the deal.

The striker, who scored 42 goals in 96 appearances for United, has signed a contract until 2024 at San Siro.

"Inter were the only club I wanted," Lukaku said upon signing.

"I'm here to bring the Nerazzurri back to the top."

Having raised eyebrows and irked United by starting the week training at former club Anderlecht in Belgium, the 26-year-old arrived in Milan overnight to complete paperwork and a medical.

Lukaku's agent Federico Pastorello had flown into London on Wednesday to push through his client's exit and end a rather uncomfortable - and at times unsavoury - process.

Despite going on the pre-season tour of Australia and Asia, knocks prevented the striker from appearing in any of United's four friendly matches.

Lukaku also missed the matches against Kristiansund and AC Milan upon their return to Europe.

Australian Associated Press