The Toffees boss has made no secret that they would love to keep the Belgian youngster, who has impressed hugely since signing on loan on transfer deadline day in September.
Lukaku has bagged nine Premier League goals already, but Martinez admits the club know they are wasting their time making any approach at the moment.
"I know Chelsea are not contemplating listening to any offers and Romelu is highly regarded there," Martinez told the Guardian.
"It's not in the agreement [to discuss a January transfer]. The agreement we have with Chelsea is that we will wait until the end of the season and as parent club they need to be the ones that give us the hint if it's possible or not.
"I rate Romelu as one of the best strikers in European football now. We want to keep Romelu as long as we can, but the reality is he's on loan for the season.
"They need to be the ones that give us the hint if it's possible or not in the future.
"As you can imagine the situation is we need to wait until the end of the season.
"Rom is enjoying his football. He knows he's here until the end of the season and I don't think it would be beneficial to anyone to go into a conversation that's not going to change the agreement we have until May."