Virgil van Dijk says he has been left with "no alternative" but to hand in a transfer request in a bid to force a move away from Southampton, as he wants to play European football.

The centre-back, who has been training alone and has not featured during pre-season, said he made the decision to request a transfer after being fined the equivalent of two weeks' wages.

Van Dijk is a long-time target for Liverpool, which apologised to Southampton in June after allegedly being accused of tapping up the defender, an incident the Anfield club described as a "misunderstanding".

In a lengthy statement released on Monday, van Dijk - reportedly valued at $A82 million - said a move from Southampton would enable him to challenge for honours.

"It is with regret that I can confirm that I have handed in a transfer request to leave Southampton Football Club," van Dijk's statement read.