One area of his search is concentrated on South America with general manager John Benson spending this week watching Honduras - from where the Latics already signed Hendry Thomas and Maynor Figueroa - play Peru.

Martinez is interested in players from both countries but would not confirm one target is Johnny Palacios, the 22-year-old younger brother of former Wigan midfielder Wilson who made a big-money January move to Sunday's opponents Tottenham.

"We really follow many players and we have to do it because we cannot have any errors in our signings," said the Spaniard.

"In every window we have to improve the squad and help the players we have here to become a stronger team.

"It is too early to talk about names but we are working hard and have been since the summer.

"We need to get the right characters and personalities and they have to bring something different to the squad."

Martinez is looking to bring in three players in January, as well as tie up some free transfers for the summer, but will not buy just for the sake of it.

Another factor to take into consideration is whether he will lose any of his squad in just over a month's time with former Wigan boss Steve Bruce expected to come in with a bid to take left-back Figueroa to Sunderland.

The Honduran is currently sidelined with a knee injury so Erik Edman, who made his first league start since the end of last season in the 1-1 draw with Fulham before the international break, will face his former club.

Martinez has been impressed with the way the Swede has recovered from an 18-month injury nightmare.

"We've been very pleased with Erik's return," said the manager.

"It was a big step for him to be able to play competitive football again against Fulham and an exciting moment for us to see him back in action.

"He's getting stronger and fitter now and he's excited about the prospect of playing against one of his former clubs.

"So we're delighted to have a player back who gives us great quality and adds a competitive edge to the squad."