Postecoglou looks to bulk up Spurs attack ahead of next season
The Australian steered Tottenham to fifth place and Europa League qualification in his first year in charge and said changes would be needed to build on the achievement when the new campaign starts in August.
After a post-season friendly against Newcastle in Melbourne on Wednesday, where Spurs lost 5-4 on penalties after the game ended 1-1, Postecoglou pinpointed the front line as a priority.
"I mean, it's no secret. You saw the way we finished the season," he said.
"We obviously lost Richarlison and Timo as well with injuries. But we're fairly light on in that area.
"We started the last season with Manor (Solomon) and (Ivan) Perisic and we were quite healthy in that front third in terms of numbers. But as the year went on, it became pretty evident we need to bulk up.
"We're obviously in Europe next year as well, so there'll be more games. So it's definitely an area of the park we'll need to strengthen."
German winger Werner joined Spurs on loan from Bundesliga club RB Leipzig in January and contributed two goals and three assists in 14 appearances before an injury ended his season early.
The London club have an option to buy Werner, with Postecoglou saying a deadline had been set on a decision.
Comfort and clarity
"Again a lot of that will depend on the negotiations between the clubs and how Timo feels," he said.
"From my perspective I'm comfortable with that situation and I'll let the other guys steer it to see what kind of outcome there is."
Postecoglou added that he was confident he would be able to keep all the players he wanted when the transfer window opens next month, with a plan already in place for the new season.
"You always understand that things can change really quickly but we've got a plan in place that I'm really comfortable with in terms of incomings and outgoings," he said.
"Whether that all comes together you just never know but having clarity about what we need to do I think helps the process."
One player who will be at Spurs again next year is playmaker James Maddison, who was called up to England's Euro 24 squad this week and scored against Newcastle to celebrate.
Maddison, who transferred from Leicester last summer, said that Tottenham can "achieve big things" under Postecoglou after his first year of working with the Australian.
"The first season of any new project is always challenging. It has its ups and downs," Maddison said after the match.
"I'm really enjoying working for him, genuinely, and I think we can achieve big things hopefully. So the first year of many, I hope."