After watching his side, who narrowly staved off relegation last season, lose 1-0 at Queens Park Rangers in the Premier League on Saturday, the Uruguayan recognised he was running out of time to secure reinforcements.
“This not my squad. There are not enough (players). We know the numbers I want to work with are not the numbers that we’ve got,” Poyet told reporters at Loftus Road.
“I don’t know what you are going to be doing the next few days, I am going to be on the phone all the time,” he added before the transfer window closes on Monday. “It’s supposed to be a day off tomorrow, but it’s not going to be.”
Poyet took over at the Stadium of Light last October, replacing controversial Italian Paolo D1 Canio, and signed a new two-year contract in May after leading the club to a 14th place finish.
Sunderland have been busy already in the transfer market, with signings including England midfielder Jack Rodwell from champions Manchester City as well as Dutch international Patrick van Aanholt.
However Poyet has also been frustrated by missing out on other targets.
“We were close a few weeks ago to a couple, but not close enough,” he said. “We are going to do something because there are important positions to fill.”
Poyet gave no names or details, having spoken earlier in the week of his frustration at leaks to the press about what Sunderland were up to.
“You do all your work, you get in contact with the club, you get in contact with the player, you research if he has the right mentality, if he has any problems, everything that’s important for you,” he said at the time.
“Then the name comes out in the Press, another club gets involved, another one offers more money, another one, another one and at the end of the day, he is not coming, so I am sorry, but no names.
“It’s been a very difficult summer.
(Editing by Ken Ferris)