Both players have represented England at youth level from the Under-18s to the Under-21s, with Nketiah scoring 35 goals in 38 appearances, while Lamptey has featured a total of 20 times for the Young Lions.
However, both Nketiah, 23, and Lamptey, 21, are yet to play for Gareth Southgate's senior side and with competition for places rife, they have both decided to pledge their commitments to Ghana.
According to GHANASoccernet.com, the process of switching nationalities has taken longer than expected, but Nketiah and Lamptey will receive full clearance by FIFA to represent that Ghanaian national team next week.
The report adds that Chelsea winger Callum Hudson-Odoi and Athletic Bilbao forward Inaki Williams are also set to represent Ghana, with their nationality switches believed to have been easier to sort out.
Ghana head coach Otto Addo has revealed that he has spoken to the incoming players and has provided an update on their situation.
"The time is limited. First of all if you've played for another country, the process is long. But it is an open secret that we have talked to a lot of players and latest by next week, we will know who will have to join us," Addo told Joy News.
"Surely we have to be very fast now. We set the limits and we want at least if somebody wants to join us or we know someone who can help us, he must be ready for the September window. For that the answer is now and hopefully next week, we will know more."
Nketiah will also be looking to hold talks with Arsenal over his future this month, as his current contract at the Emirates Stadium is due to expire on June 30.
As for Brighton's Lamptey, he is understood to have withdrawn from the most recent England Under-21s squad to finalise his switch to Ghana.
Ghana have been drawn in Group H for the upcoming World Cup in Qatar, along with Portugal, Uruguay and South Korea.