United want to keep Ighalo for the remainder of the season but privately insist the "ball is in Shanghai's court" with the delayed Chinese Super League season set to start in June.
The initial deal agreed in January is due to expire this weekend and the two clubs will have to reach a fresh agreement for the striker to stay at Old Trafford.
Shanghai have been reluctant to sanction an extension but negotiations are ongoing.
Shanghai want Ighalo back for the start of their domestic campaign, but there is confusion over whether he would immediately be allowed back into China.
Restrictions put in place on March 28 halted foreign nationals from entering the country -- even if they hold valid visas -- in an effort to combat the coronavirus outbreak.
United manager Ole Gunnar Solskjaer is keen to keep the 30-year-old, who has been training at Carrington this week, with his side facing as many as 18 games in two months following the restart in order to complete campaigns in the Premier League, FA Cup and Europa League.
Ighalo has impressed, scoring four goals in eight games, but Solskjaer has welcomed back Marcus Rashford after injury to bolster his squad and is said to be "relaxed" about the situation.
"The loan deal went until the end of May now, so obviously he's supposed to be going back," Solskjaer told MUTV on Tuesday.
"We're in dialogue. They've been great towards us, his club, and allowed him to play for his dream club.
"It's been a dream for him and hopefully he can finish off what he started, hopefully with a trophy for us. At the moment, nothing has been agreed. Their league is going to get started soon so we're just waiting to see."