Abidjan-born Zaha grew up in England and won two caps for the Three Lions, but because they were in friendly games he is allowed to switch allegiance.
"We have written to Fifa and expect Zaha's switch to be approved," said Ivorian FA vice-president Malick Tohe.
However, Southgate said: "We are still hopeful that we can speak to Wilf."
In the past maybe England was the better option but now [Ivory Coast and England] are more or less the same
Southgate, who managed the Crystal Palace winger for England Under-21s, has not ruled out the chance to select him again, this time for the senior side, despite Zaha's request to Fifa to switch allegiance.
"He's a player I've obviously worked with. At the time, I had him with the Under-21s. The first few months he played very well for us...then he had a difficult period for his club.
"He had a loan spell at Cardiff that didn't go so well and at the stage we had players like Tom Ince, who was performing better in the Championship out wide for us, so he dipped out of that group.
"Then obviously over the last couple of years, with respect, no-one was questioning him not being in our squad last summer (at the European Championships)."
Asked if the player's decision was now too far down the line, Southgate replied: "I would like to speak to him before we make a decision and happy to make that happen."
Zaha's slip down the pecking order for England opened up the chance for Ivory Coast to persuade the 24-year-old to switch to the Elephants.
And Tohe told BBC Sport why he believes playing for Ivory Coast has great appeal.
"Ivory Coast is valued, the national team is always at the World Cup, we won the 2015 Africa Cup of Nations. Players know it is a good team to play with."
When asked how the Ivorians put their case to Zaha, Tohe said: "We told him 'you have two options and in the past maybe England was the better option but now they are more or less the same'.
"Zaha was born in Ivory Coast, he will be joining the African champions... there is the same exposure for Ivory Coast as for the England team."
Ivory Coast are confident Wilfried Zaha will soon be part of their team, but new England boss Gareth Southgate has not given up on the forward.